December 11, 2023
The HTTP 404 error is one of the most common issues users encounter on the web. Despite its familiarity, repeated or unresolved occurrences can harm search engine rankings and erode user trust.
This error can also signal deeper structural or configuration problems. Addressing it requires both a clear understanding of what the error represents and a disciplined approach to diagnosing and resolving its causes.
This guide breaks down what a 404 means, the main causes, and how to identify and fix it effectively—with practical technical solutions for developers and site owners.
This error can also signal deeper structural or configuration problems. Addressing it requires both a clear understanding of what the error represents and a disciplined approach to diagnosing and resolving its causes.
This guide breaks down what a 404 means, the main causes, and how to identify and fix it effectively—with practical technical solutions for developers and site owners.
A 404 error is a standard HTTP status code that signals the requested page could not be found on the server. This error typically appears when a user attempts to access a page that has been deleted, moved, or never existed in the first place.
For website owners, understanding 404 errors is essential—not only do they disrupt the user journey, but they can also negatively affect search engine rankings if left unresolved. Search engines interpret frequent 404 errors as a sign of poor site maintenance, which can lower your site’s visibility in search results.
For website owners, understanding 404 errors is essential—not only do they disrupt the user journey, but they can also negatively affect search engine rankings if left unresolved. Search engines interpret frequent 404 errors as a sign of poor site maintenance, which can lower your site’s visibility in search results.
When a browser requests a resource that does not exist at the specified location, the server returns a 404 status code—a direct indication that the requested path is not valid. The 404 error is a standard HTTP status code, where HTTP stands for Hypertext Transfer Protocol, the foundational protocol used for communication between browsers and web servers.
HTTP status codes, such as 404, indicate the result of a user's request, and in this case, the 404 error means that a specific page could not be found on the server. The message varies depending on the server or framework configuration, but whether it reads “Error 404: Not Found” or “HTTP 404 – File Not Found,” the underlying meaning is the same: the server was reached, but the resource was not. The URL (Uniform Resource Locator) specifies the address of the requested resource.
HTTP status codes, such as 404, indicate the result of a user's request, and in this case, the 404 error means that a specific page could not be found on the server. The message varies depending on the server or framework configuration, but whether it reads “Error 404: Not Found” or “HTTP 404 – File Not Found,” the underlying meaning is the same: the server was reached, but the resource was not. The URL (Uniform Resource Locator) specifies the address of the requested resource.
Source: Press Up
This may occur because the URL is mistyped, the content has been deleted, or the file path has been altered without proper redirect rules in place. In web infrastructure terms, the 404 is a client-side error, but its origin often lies in server or configuration changes rather than user action alone. The 404 is classified as a client error within the family of HTTP status codes.
Google 404 error page
A persistent 404 problem is more than a cosmetic issue. From a user experience perspective, it interrupts the navigation flow and often drives visitors away. From an SEO perspective, it interrupts crawling and indexing, potentially wasting valuable link equity and lowering your visibility in search results.
For engineers, frequent 404s suggest weaknesses in change management: perhaps URL updates were deployed without redirect mapping, or outdated resources were removed without verifying inbound link references. Excessive or improperly handled 404 errors can confuse search engines, making it harder for them to index your content accurately. Over time, such oversights accumulate, weakening both the technical integrity and the public perception of a site.
For engineers, frequent 404s suggest weaknesses in change management: perhaps URL updates were deployed without redirect mapping, or outdated resources were removed without verifying inbound link references. Excessive or improperly handled 404 errors can confuse search engines, making it harder for them to index your content accurately. Over time, such oversights accumulate, weakening both the technical integrity and the public perception of a site.
Although user typos can trigger the error, this is often a user error that can result in a 404. Production environments reveal a broader spectrum of causes. Pages and files are sometimes deleted during content refresh cycles without corresponding redirect rules, or are moved to new locations as part of a site restructuring, resulting in content that no longer exists. Additionally, issues can also originate from the website owner's side, such as server or configuration changes.
In Apache or Nginx setups, server misconfiguration—such as misconfigured .htaccess files or rewrite directives—can make valid resources inaccessible. DNS misrouting can prevent requests from even reaching the correct server, while in distributed architectures a CDN may serve outdated cache entries pointing to now-missing objects.
Modern single-page applications introduce additional complexity—without proper server-side fallback to index.html, client-side routing failures can result in 404s for otherwise valid application states, as the website's server returns a 404 error.
API-driven sites face their own variant: deprecated endpoints, if removed without versioning or backward-compatible aliases, can produce 404 responses that ripple through dependent services.
In Apache or Nginx setups, server misconfiguration—such as misconfigured .htaccess files or rewrite directives—can make valid resources inaccessible. DNS misrouting can prevent requests from even reaching the correct server, while in distributed architectures a CDN may serve outdated cache entries pointing to now-missing objects.
Modern single-page applications introduce additional complexity—without proper server-side fallback to index.html, client-side routing failures can result in 404s for otherwise valid application states, as the website's server returns a 404 error.
API-driven sites face their own variant: deprecated endpoints, if removed without versioning or backward-compatible aliases, can produce 404 responses that ripple through dependent services.
Common Causes Table
| Cause | Technical Description | Example Scenario |
| Deleted or moved content | Page or file removed or relocated without a redirect | /blog/article-1 moved to /articles/article-1 but no 301 set, resulting in a dead link |
| Typos in URL | User or developer enters incorrect resource path | Link points to /produts instead of /products |
| Misconfigured .htaccess or Nginx rules | Incorrect rewrite or redirect logic blocks access | Apache RewriteRule missing, causing image paths to fail |
| DNS misconfiguration | Domain resolves to wrong IP or not at all | example.com points to outdated hosting provider |
| CDN cache issues | Cached references to deleted or outdated files | JS bundle missing after deployment due to stale CDN cache |
| SPA client-side routing failure | No server fallback to application entry point | /dashboard route returns 404 instead of loading index.html |
| API endpoint removal | Legacy endpoint removed without backward compatibility | /api/v1/users deleted without alias to /api/v2/users |
Finding 404 errors efficiently requires visibility into both external crawl data and internal server logs, especially error logs, which are a key resource for identifying 404 errors and diagnosing server-side issues.
For those managing WordPress sites, the WordPress dashboard offers plugins and features to monitor 404 errors and set up redirects to correct pages. It is important to crawl the site regularly to catch issues early. By regularly checking for 404 errors, website owners can prevent poor user experience, reduce the number of broken links, and ensure visitors always find the content they’re looking for. These practices help maintain the website's health.
Search engines expose their findings via tools such as Google Search Console, which aggregates all “Not Found” reports detected during crawling. SEO audit platforms like Ahrefs or SEMrush can simulate similar scans from the public web, identifying broken inbound and outbound links.
From the engineering side, parsing Apache access.log or Nginx error.log files can uncover 404 patterns in real time. On high-traffic systems, these checks are best automated — for instance, integrating a link validation step into a CI/CD pipeline ensures that broken references are caught before deployment.
Once an error is identified, confirming its authenticity is essential. A quick terminal request such as:
For those managing WordPress sites, the WordPress dashboard offers plugins and features to monitor 404 errors and set up redirects to correct pages. It is important to crawl the site regularly to catch issues early. By regularly checking for 404 errors, website owners can prevent poor user experience, reduce the number of broken links, and ensure visitors always find the content they’re looking for. These practices help maintain the website's health.
Search engines expose their findings via tools such as Google Search Console, which aggregates all “Not Found” reports detected during crawling. SEO audit platforms like Ahrefs or SEMrush can simulate similar scans from the public web, identifying broken inbound and outbound links.
From the engineering side, parsing Apache access.log or Nginx error.log files can uncover 404 patterns in real time. On high-traffic systems, these checks are best automated — for instance, integrating a link validation step into a CI/CD pipeline ensures that broken references are caught before deployment.
Once an error is identified, confirming its authenticity is essential. A quick terminal request such as:
curl -I https://example.com/missing-page
will verify whether the server is genuinely returning a 404 Not Found or disguising a “soft” 404 with a 200 status code.
For DNS-related cases, tools like dig and nslookup help confirm hostname resolution:
For DNS-related cases, tools like dig and nslookup help confirm hostname resolution:
dig example.com
nslookup example.com
These reveal whether the domain points to the expected IP address, allowing engineers to isolate routing or propagation issues.
DNS settings are the backbone of how users reach your website. If your DNS settings are incorrect, users trying to access your site may be sent to the wrong hosting server or receive a 404 error because the requested domain cannot be found.
Website owners should regularly review their DNS settings to ensure they point to the correct server and avoid unnecessary downtime or missing pages.
Website owners should regularly review their DNS settings to ensure they point to the correct server and avoid unnecessary downtime or missing pages.
Practical Diagnostics
# Check A and CNAME records
dig example.com
dig www.example.com CNAME
# Compare authoritative nameservers
whois example.com | grep "Name Server"
Example Fix
- Ensure A and AAAA records point to the correct hosting IP
- Add www → non-www (or reverse) 301 redirect to avoid duplicate content and broken paths
- Verify all subdomains are mapped to active hosts
Beyond DNS, configuration errors within your website—such as incorrect file permissions or a misconfigured .htaccess file—can also result in 404 errors.
For example, if file permissions are set incorrectly, the web server may block access to certain resources, causing a 404 response even if the file exists. Regularly auditing your DNS settings and website configuration helps prevent these issues, ensuring users can always reach the content they’re looking for and reducing the risk of broken or dead links.
Beyond DNS, misconfigured website settings can directly cause 404 errors even when the files themselves are present on the server. In Apache or Nginx environments, incorrect rewrite rules, missing directory index settings, or restrictive access controls can prevent the server from delivering valid pages. In CMS-driven sites such as WordPress, Joomla, or Drupal, incorrect permalink structures or disabled routing modules can render entire sections of the site unreachable.
Security plugins or firewall rules may also block legitimate requests, resulting in false 404s. The solution lies in systematically reviewing server configuration files (.htaccess, nginx.conf), CMS permalink and routing settings, and any middleware that processes requests before they reach the content layer.
Security plugins or firewall rules may also block legitimate requests, resulting in false 404s. The solution lies in systematically reviewing server configuration files (.htaccess, nginx.conf), CMS permalink and routing settings, and any middleware that processes requests before they reach the content layer.
Practical Diagnostics
# Apache syntax test
apachectl configtest
# Nginx syntax test
nginx -t
Example Fix
In Apache .htaccess:
DirectoryIndex index.php index.html
In Nginx for Single Page Apps:
location / {
try_files $uri /index.html;
}
- In WordPress: Settings → Permalinks → Save Changes (regenerates .htaccess)
- Disable security plugins temporarily to rule out false 404 responses
When changes are made, staging environments should be used to verify routing behavior before deploying to production, ensuring that no valid paths are unintentionally broken.
The correct fix depends on the root cause. For moved content, implementing redirects is the most reliable solution. A permanent redirect ensures users and search engines are sent from the old url to the new url. In Apache, a simple 301 can be added to .htaccess:
Redirect 301 /old-page /new-page
For Nginx, an equivalent directive might be placed in the server block:
rewrite ^/old-page$ /new-page permanent;
When dealing with multiple redirects, mapping rules from a CSV or text file into rewrite configurations can reduce manual errors. In SPAs, ensure that the server routes all non-API requests to the application entry point.
Nginx SPA fallback:
location / {
*try_files $uri /index.html;*
}
This ensures client-side routing does not trigger false 404s for valid paths.
When a user requests a page, the server attempts to deliver the requested resource. If the resource is missing, a 404 error is returned. Broken links, especially external links pointing to missing pages, should be updated or redirected to maintain SEO value and user experience.
API-driven applications should implement endpoint versioning to avoid breaking existing clients, keeping old routes functional until they can be safely deprecated.
When a user requests a page, the server attempts to deliver the requested resource. If the resource is missing, a 404 error is returned. Broken links, especially external links pointing to missing pages, should be updated or redirected to maintain SEO value and user experience.
API-driven applications should implement endpoint versioning to avoid breaking existing clients, keeping old routes functional until they can be safely deprecated.
Solutions Table
| Solution | Implementation | Example Code / Command |
| Permanent Redirect for Moved Pages | Use 301 redirect to preserve SEO and user access, fixing broken pages caused by URL changes | Redirect 301 /old-page /new-page |
| Correct Internal Links | Audit content and update broken references to prevent broken pages | Use Screaming Frog to export link report and fix in CMS |
| Restore Removed High-Value Content | Re-upload deleted pages with same URL if high traffic/backlinks to resolve broken pages | Restore from CMS backup or Git version history |
| Fix .htaccess Rewrite Rules | Ensure correct mapping of URLs to resources to avoid broken pages | RewriteRule ^products$ products.php [L] |
| Validate DNS Configuration | Confirm domain points to correct hosting IP | dig example.comnslookup example.com |
| Clear CDN Cache | Purge outdated references to removed files | Cloudflare: Purge Cache → Purge Everything |
| Configure SPA Fallback | Serve index.html for unknown routes | location / { try_files $uri /index.html; } |
| Implement API Versioning | Maintain old endpoints until migration is complete | /api/v1/users → /api/v2/users with alias route |
Even with rigorous prevention, some 404s are inevitable. A well-designed error page can turn a potential drop-off into a retained session. Instead of presenting a blank “Not Found” message, the page should display a clear error message, such as a found error message like "404 Page Not Found." It should also offer context, navigation options, and—if applicable—a search interface to help users recover. The design should integrate seamlessly with the rest of the site, avoiding the sense that the user has been dropped into an entirely different space. From an SEO standpoint, the page must still return a true 404 status to prevent unwanted indexing, but its content can guide visitors toward relevant material.
Example minimal Apache configuration for a custom error page:
Example minimal Apache configuration for a custom error page:
ErrorDocument 404 /custom-404.html
For Nginx:
error_page 404 /custom-404.html;
location = /custom-404.html {
root /var/www/html;
internal;
}
Automated tools are the fastest and most reliable way to detect, monitor, and address 404 errors before they begin to damage SEO performance or user experience. 404 errors and broken links can negatively impact your search rankings and your website's performance by reducing indexing opportunities and link equity.
For most site owners, the first line of defense is Google Search Console, which continuously scans indexed URLs and reports any “Not Found” errors it encounters. Google rely on accurate crawling and accessible pages to evaluate your site, so addressing these errors is crucial for maintaining visibility.
For most site owners, the first line of defense is Google Search Console, which continuously scans indexed URLs and reports any “Not Found” errors it encounters. Google rely on accurate crawling and accessible pages to evaluate your site, so addressing these errors is crucial for maintaining visibility.
By reviewing the “Pages → Not Indexed → Not Found (404)” section, you can quickly see which URLs are affected, when they were last crawled, and whether the problem persists.
For deeper technical audits, tools like Screaming Frog SEO Spider or Sitebulb can simulate a search engine crawl of your site, identifying both internal and external broken links. This is particularly valuable for large-scale sites with thousands of URLs, where manual checks are impractical. Screaming Frog, for example, can export all URLs returning a 404 status into a CSV file, making it easy to prioritize fixes based on traffic or backlink data.
For competitive monitoring, platforms such as Ahrefs and SEMrush can identify broken inbound links from other websites that point to your missing pages. These tools not only help you fix the 404 internally, but also enable you to reclaim lost link equity by reaching out to referring domains with updated URLs or redirects.
On the server side, log analyzers like GoAccess or AWStats can process Apache or Nginx logs in real time, revealing 404 patterns that automated crawlers might miss—for example, requests from API clients, outdated mobile apps, or bots hitting deprecated endpoints.
For teams using continuous integration, adding automated link checking tools such as Broken Link Checker, Linkinator, or custom scripts into your CI/CD pipeline ensures that any new content or deployment is scanned for broken URLs before going live.
To maintain optimal SEO health, it's important to crawl your site regularly to catch issues like 404 errors early.
Finally, integrating monitoring alerts (e.g., via Grafana, New Relic, or custom Slack webhooks) allows you to receive instant notifications when a spike in 404 responses occurs. This real-time visibility helps quickly determine whether the cause is a deployment error, DNS issue, or a surge of malformed requests, enabling rapid resolution before it impacts a large portion of users.
To maintain optimal SEO health, it's important to crawl your site regularly to catch issues like 404 errors early.
Finally, integrating monitoring alerts (e.g., via Grafana, New Relic, or custom Slack webhooks) allows you to receive instant notifications when a spike in 404 responses occurs. This real-time visibility helps quickly determine whether the cause is a deployment error, DNS issue, or a surge of malformed requests, enabling rapid resolution before it impacts a large portion of users.
404 Monitoring Tools Overview
| Tool / Platform | Primary Use Case | Best For |
| Google Search Console | Detects indexed URLs returning 404, with crawl data | Ongoing monitoring and SEO health checks |
| Screaming Frog SEO Spider | Crawls entire site to find internal & external 404s | Large websites with complex internal linking |
| Sitebulb | Visualizes site structure & link issues | Agencies and teams needing visual reports |
| Ahrefs / SEMrush | Finds broken inbound links from other domains | Link reclamation and competitive SEO analysis |
| GoAccess / AWStats | Parses server logs for real-time 404 patterns | Detecting API/app-specific 404s missed by web crawlers |
| Broken Link Checker / Linkinator | Automated pre-deployment link testing | CI/CD integration and QA before site updates |
| Grafana / New Relic Alerts | Sends instant alerts on 404 spikes | Rapid response to outages or mass link failures |
A 404 page should not be a dead end—it is a chance to redirect lost visitors back into the site’s main flow. A high-quality error page combines functional navigation, clear messaging, and a consistent visual style that matches the rest of the website. The message should be written in plain language, acknowledging that the requested page is missing, and ideally adding a touch of personality or brand tone to soften the frustration.
Essential elements of an effective 404 page:
SEO note! While the content can be helpful for users, the server must return an actual 404 HTTP status code—this tells search engines not to index it and prevents soft-404 issues.
Essential elements of an effective 404 page:
- Clear error message: e.g., “Sorry, we couldn’t find that page.”
- Search functionality: lets users find the right content without going back to Google.
- Navigation links: direct to homepage, top categories, or most visited content.
- Contact option: quick way to report a broken link or request missing information.
- Consistent branding: same fonts, colors, and style as the rest of the site to maintain trust.
SEO note! While the content can be helpful for users, the server must return an actual 404 HTTP status code—this tells search engines not to index it and prevents soft-404 issues.
Schematic Layout of an Ideal 404 Page
HTTP 404 errors are inevitable in the lifespan of any website or application, including a WordPress site, but their frequency and impact are entirely within an engineer’s control.
By combining systematic detection, accurate diagnosis, and targeted resolution with preventative operational practices, it is possible to maintain a clean, reliable user experience and safeguard search visibility.
Ultimately, the absence of recurring 404s is less a sign of perfect systems than of mature processes—the kind that turn inevitable errors into rare, quickly resolved events.
By combining systematic detection, accurate diagnosis, and targeted resolution with preventative operational practices, it is possible to maintain a clean, reliable user experience and safeguard search visibility.
Ultimately, the absence of recurring 404s is less a sign of perfect systems than of mature processes—the kind that turn inevitable errors into rare, quickly resolved events.
404 errors are inevitable, but their impact on user trust and search visibility is entirely manageable with the right approach. By identifying root causes quickly, setting up proper redirects, and monitoring with tools like Google Search Console, you can keep your site accessible, optimized, and professional.
If you want the peace of mind that comes from expert support, choose a hosting provider that ensures uptime, speed, and proactive error management—like Scalesta.
If you want the peace of mind that comes from expert support, choose a hosting provider that ensures uptime, speed, and proactive error management—like Scalesta.
Should I create a separate page for the 404 error?
Having a separate page dedicated to this error can be beneficial as it helps users find what they’re looking for if they have encountered an issue. The website owner is responsible for creating and managing the custom 404 page and implementing 301 redirects to guide visitors from broken URLs back to relevant pages. Depending on your content management system (CMS), you might be able to create a custom page specifically for these types of errors. Utilizing 301 redirects will help keep users engaged and prevent them from leaving due to the broken link.
How to monitor 404 errors via Google Search Console?
You have the option to monitor 404 errors detected by Google’s crawlers through Google Search Console. After verifying your site with Google Search Console, navigate to Crawl → Crawl Errors → Not found to access a compilation of 404 errors encountered by Google. This method stands out as one of the simplest approaches. Additionally, it excels in terms of efficiency as it doesn’t necessitate third-party plugins or supplementary scans on your website.
What do broken links mean?
Broken links refer to hyperlinks that point to web pages, images, documents, or other resources that no longer exist or cannot be accessed. When a user clicks on a link, it results in a “404 Not Found” error or a similar message indicating that the intended content or page is unavailable.
Several reasons can lead to broken links:
Broken links negatively impact user experience and can also affect a website’s search engine ranking. Regularly checking for and fixing links is essential to ensure a seamless browsing experience for users and to maintain the health and integrity of a website.
Having a separate page dedicated to this error can be beneficial as it helps users find what they’re looking for if they have encountered an issue. The website owner is responsible for creating and managing the custom 404 page and implementing 301 redirects to guide visitors from broken URLs back to relevant pages. Depending on your content management system (CMS), you might be able to create a custom page specifically for these types of errors. Utilizing 301 redirects will help keep users engaged and prevent them from leaving due to the broken link.
How to monitor 404 errors via Google Search Console?
You have the option to monitor 404 errors detected by Google’s crawlers through Google Search Console. After verifying your site with Google Search Console, navigate to Crawl → Crawl Errors → Not found to access a compilation of 404 errors encountered by Google. This method stands out as one of the simplest approaches. Additionally, it excels in terms of efficiency as it doesn’t necessitate third-party plugins or supplementary scans on your website.
What do broken links mean?
Broken links refer to hyperlinks that point to web pages, images, documents, or other resources that no longer exist or cannot be accessed. When a user clicks on a link, it results in a “404 Not Found” error or a similar message indicating that the intended content or page is unavailable.
Several reasons can lead to broken links:
- Page deletion or removal: if a web page is deleted or removed without proper redirection, any links pointing to that page become broken.
- Changes in URL structure: modifications in a website’s URL structure might render previously linked pages inaccessible.
- Content relocation: when content is relocated within a website or to a different domain without implementing proper redirects, links to the old location become broken.
- Typos or mistakes: human errors in manually typing or inputting URLs can result in broken links.
Broken links negatively impact user experience and can also affect a website’s search engine ranking. Regularly checking for and fixing links is essential to ensure a seamless browsing experience for users and to maintain the health and integrity of a website.
