Error Status Code

Pages returning HTTP error status codes are either completely inaccessible to users and search engines or delivering broken experiences that waste crawl budget, damage rankings, and frustrate visitors who expected functional content.

HTTP status codes are the invisible handshake between your server and every visitor, whether human or bot. When a page returns an error code like 404 (Not Found), 500 (Server Error), or 301 (Permanent Redirect), it signals a problem that prevents normal access. These errors directly harm SEO by making content undiscoverable, wasting limited crawl budget on broken URLs, and creating negative user signals that suppress rankings across your entire domain.

What Are HTTP Status Codes?

HTTP status codes are three-digit responses sent by web servers in the HTTP header of every page request. They communicate whether the request succeeded, failed, or requires additional action. These codes exist in the invisible layer of web communication, users rarely see them unless something goes wrong, but search engine crawlers rely on them to determine which pages to index, follow, or ignore.

Status codes are grouped into five categories:

2xx Success Codes ($200-299$): These indicate the request was successful and the page loaded normally. The most common is $200$ OK, meaning the page is accessible and ready to index. This is the only range that allows normal indexing and ranking.

3xx Redirection Codes ($300-399$): These tell the browser or bot to look elsewhere for the content. $301$ Moved Permanently signals a permanent location change and passes most link equity to the new URL. $302$ Found indicates a temporary redirect that doesn't transfer SEO value. $307$ and $308$ are similar but preserve the HTTP method (GET, POST). While redirects aren't inherently errors, they add latency and can signal site structure problems if overused.

4xx Client Error Codes ($400-499$): These indicate the request failed due to client-side issues. $404$ Not Found means the URL doesn't exist on the server. $403$ Forbidden signals access restrictions. $410$ Gone indicates the page was intentionally removed and won't return. These codes tell search engines not to waste crawl budget trying to access these URLs again.

5xx Server Error Codes ($500-599$): These indicate the server failed to fulfill a valid request. $500$ Internal Server Error is a generic failure. $502$ Bad Gateway and $503$ Service Unavailable often indicate temporary server problems or downtime. $504$ Gateway Timeout means the server took too long to respond. These codes tell crawlers to try again later, but repeated errors can lead to deindexing.

1xx Informational Codes ($100-199$): Rarely seen, these provide preliminary responses during long-running requests. They don't affect SEO meaningfully in most contexts.

For SEO purposes, only $2xx$ codes represent fully functional, indexable pages. Every other range indicates a problem that prevents normal indexing, whether temporary or permanent, intentional or accidental.

The SEO Impact

Pages returning error status codes create cascading SEO problems that harm individual page performance, waste crawl budget, and damage domain-wide authority signals.

Complete Loss of Indexing and Rankings: Search engines will not index or rank pages that consistently return error codes. A $404$ error tells Google the page doesn't exist, so it will be dropped from the index entirely. A $500$ server error signals the page is unavailable, leading to temporary suppression and eventual deindexing if the error persists for days or weeks. If the page previously ranked and drove organic traffic, that traffic disappears overnight once the error is detected.

Wasted Crawl Budget on Broken URLs: Google allocates a finite crawl budget to each site based on authority, server capacity, and site size. When crawlers encounter error pages, they waste crawl requests on non-functional URLs that could have been spent discovering or re-indexing valuable content. Sites with thousands of $404$ errors force Google to crawl dead pages repeatedly, slowing discovery of new content and reducing crawl frequency for important pages.

Negative User Experience Signals: When users land on error pages from search results, backlinks, or internal navigation, they immediately bounce. High bounce rates, zero time on page, and frustrated return-to-search behaviors send powerful negative signals to Google's algorithm. If multiple pages on your site return errors, Google may interpret your entire domain as low-quality or poorly maintained, suppressing rankings across unrelated pages.

Lost Link Equity from Backlinks: If external sites link to a page that now returns a $404$ or $500$ error, that link equity is wasted. The authority those backlinks could have passed to your site evaporates because the destination doesn't exist or isn't accessible. For high-authority backlinks, this represents significant lost ranking potential that could have been preserved with proper redirects.

Broken Internal Link Structures: Error pages within your site create dead ends in your internal linking architecture. Pages that link to error URLs don't pass link equity effectively, and crawlers can't follow those links to discover deeper content. This fragments your site's link graph, isolating important pages and preventing them from accumulating the internal authority they need to rank competitively.

Search Console Warnings and Coverage Issues: Google Search Console flags error status codes under the Coverage report, alerting you to indexing problems. Large numbers of errors can trigger manual review flags or sitewide quality assessments that harm rankings. Sites with persistent coverage errors may see reduced crawl rates, delayed indexing of new content, or suppressed visibility in search results.

Redirect Chains and Performance Penalties: While $3xx$ redirects aren't always errors, chains of multiple redirects (e.g., URL A → URL B → URL C → URL D) create latency, confuse crawlers, and dilute link equity. Each hop in a redirect chain loses approximately 10-15% of SEO value. Pages at the end of long redirect chains may never be fully crawled or indexed, effectively making them invisible in search.

For e-commerce sites, product pages returning $404$ errors after inventory runs out represent lost revenue and wasted ad spend if paid campaigns still drive traffic to those URLs. For content sites, error pages in high-traffic blog posts or resource pages can cause 50-100% traffic loss overnight if not caught and fixed quickly. Even temporary $5xx$ errors during peak crawl times can delay indexing of critical content by weeks.

Common Causes

Deleted Pages Without Redirects: When products are discontinued, blog posts are removed, or pages are deleted during site redesigns, the URLs often remain indexed in Google or linked from external sites. If no $301$ redirect is implemented to point the old URL to a relevant replacement, visitors encounter $404$ errors. This is especially common after CMS migrations, inventory management automation in e-commerce, or content audits where low-performing pages are removed without redirect planning.

Server Misconfigurations or Downtime: Hosting issues, server overload, incorrect .htaccess or nginx.conf configurations, or firewall rules can cause pages to return $500$ Internal Server Error or $503$ Service Unavailable codes. Temporary downtime during maintenance windows, failed deployments, or DDoS attacks can also trigger these errors. If monitoring isn't in place, errors may persist for hours or days before anyone notices.

Broken URL Parameters or Routing Errors: Dynamic URLs with query parameters (e.g., /product?id=12345) or SEO-friendly URLs handled by framework routing can break if the backend logic changes. A page that worked at /blog/2023/article-title might return $404$ if the routing rule is accidentally removed or modified. This is common in custom-built sites, headless CMS setups, or frameworks like Next.js or Rails where route definitions change across versions.

Incorrect Redirect Implementations: Developers sometimes implement redirects using JavaScript or meta refresh tags instead of proper server-level $301$ or $302$ responses. Search engines may interpret these as $200$ responses with instant redirects, leading to confusion, crawl inefficiency, or soft $404$ detection (where Google sees a $200$ code but the content appears to be an error page). Similarly, wildcard redirects that catch all $404$s and send them to the homepage with $200$ codes mask real errors and confuse search engines.

Permission or Authentication Issues: Pages requiring login or special access permissions may return $403$ Forbidden codes when crawlers attempt to access them. If these pages should be indexable (e.g., public content accidentally behind a login wall), the $403$ prevents indexing. Conversely, accidentally exposing restricted content without authentication checks can create security vulnerabilities masked by error codes when security rules are hastily applied.

Expired SSL Certificates or HTTPS Errors: If your SSL certificate expires or is misconfigured, browsers and crawlers may refuse to load the page, resulting in connection errors that appear as $5xx$ codes or timeouts. Mixed content warnings (HTTP resources on HTTPS pages) or forced HTTPS redirects that loop endlessly can also trigger error states that prevent normal page access.

How Zignalify Detects This

Zignalify captures the HTTP status code returned by your server when our crawler requests each page. This status code is the server's first response before any HTML content is sent, it tells the crawler whether the page is accessible, redirected, or encountering an error.

Our detection process is straightforward. When we crawl a page, we record the exact status code the server responds with. We then evaluate whether that code falls within the $2xx$ range, which represents successful responses. The $2xx$ range includes codes like $200$ (OK), $201$ (Created), and $204$ (No Content), all of which indicate the request was fulfilled successfully and the page is accessible.

If the status code is anything outside the $2xx$ range, Zignalify flags the page as having an error status code. This includes $3xx$ redirection codes (like $301$ or $302$), $4xx$ client error codes (like $404$ or $403$), and $5xx$ server error codes (like $500$ or $503$). While redirects are technically not errors in all contexts, they still indicate the page is not serving content directly at the requested URL, which can signal structural or configuration issues that need attention.

Our crawler checks both desktop and mobile versions of your pages to ensure status codes are consistent across user agents. Some sites return different status codes for mobile crawlers due to mobile-specific configurations, redirects to mobile subdomains, or responsive design edge cases. If we detect a discrepancy, like $200$ on desktop but $404$ on mobile, we flag the page to alert you to the inconsistency.

When a page fails this check, Zignalify records the exact status code in the issue details, for example, "This page returns a $404$ status code" or "This page returns a $503$ status code." This specificity helps you understand the nature of the problem immediately, whether it's a missing page, a server error, or a redirect that might need optimization.

This detection approach mirrors how search engine crawlers evaluate your site. Google, Bing, and other search engines rely entirely on HTTP status codes to decide which pages to index, which to ignore, and which to retry later. By flagging non-$2xx$ status codes, Zignalify helps you identify and fix problems before they impact your search rankings or waste crawl budget.

Step-by-Step Fix

1. Audit Pages Flagged by Zignalify

Log in to your Zignalify dashboard and navigate to the Audit Results page. Filter issues by the "Error Status Code" rule to see all affected URLs. Export this list as a CSV for easier management and categorization.

Review the status codes reported for each page:

$404$ Not Found: The page doesn't exist at this URL
$500$ Internal Server Error: Server-side problem preventing page load
$301/302$ Redirects: Page is redirecting (may need optimization)
$403$ Forbidden: Access restrictions preventing crawler access
$503$ Service Unavailable: Temporary server unavailability (often hosting or load issues)

Prioritize fixing $4xx$ and $5xx$ errors on high-traffic pages, pages with strong backlink profiles, or pages critical to conversions.

2. Diagnose the Root Cause

For each flagged URL, determine why the error is occurring:

For $404$ errors:

Check if the page was intentionally deleted or if the URL is simply incorrect
Search your site's navigation and internal links to see if anything still points to this URL
Use Google Search Console to check if the URL has inbound backlinks or historical traffic

For $500/503$ errors:

Check server logs to identify the specific error (database connection failures, script timeouts, permission issues)
Test the URL manually in multiple browsers to see if the error is consistent
Verify your hosting provider isn't experiencing downtime or resource limits

For $301/302$ redirects:

Trace the redirect chain to see where the URL ultimately leads
Determine if the redirect is necessary or if the URL could serve content directly

3. Implement Appropriate Fixes

For $404$ Errors (Page Deleted or Moved):

If the page was intentionally removed and no suitable replacement exists, leave the $404$ but ensure your $404$ error page is helpful:

<!-- Good 404 page includes navigation and search -->
<div class="error-page">
  <h1>Page Not Found</h1>
  <p>The page you're looking for doesn't exist or has been moved.</p>
  <a href="/">Return to Homepage</a>
  <form action="/search">
    <input type="text" placeholder="Search our site..." />
    <button type="submit">Search</button>
  </form>
</div>

If a suitable replacement page exists, implement a $301$ redirect at the server level.

For Apache (.htaccess):

# Redirect single page
Redirect 301 /old-page-url /new-page-url

# Redirect entire directory
RedirectMatch 301 ^/old-directory/(.*)$ /new-directory/$1

For Nginx (nginx.conf):

# Redirect single page
location = /old-page-url {
    return 301 /new-page-url;
}

# Redirect pattern
location ~ ^/old-directory/(.*)$ {
    return 301 /new-directory/$1;
}

For $500$ Server Errors:

Identify and fix the underlying server issue:

Check error logs: Access your server's error logs (often in /var/log/nginx/error.log or via hosting control panel)
Fix script errors: If a PHP, Node.js, or Python script is crashing, debug the code and fix syntax errors, missing dependencies, or runtime exceptions
Increase resource limits: If errors are caused by timeouts or memory limits, adjust php.ini settings, Node.js heap size, or server resources
Test database connections: Verify database credentials, connection strings, and query performance

For $503$ Service Unavailable:

This often indicates temporary server overload or maintenance mode:

Check hosting capacity: Ensure your hosting plan can handle current traffic levels
Disable maintenance mode: If you enabled maintenance mode and forgot to disable it, remove the maintenance flag
Investigate traffic spikes: Use analytics to check if a traffic surge is overwhelming your server

4. Platform-Specific Implementation

For WordPress:

Use plugins to manage redirects instead of editing .htaccess directly:

1. Install "Redirection" or "Simple 301 Redirects" plugin
2. Go to Tools → Redirection
3. Enter the old URL (source) and new URL (target)
4. Select "301 Permanent" as the redirect type
5. Click "Add Redirect"

For server errors, check your hosting provider's error logs or contact support for assistance.

For Shopify:

Shopify automatically creates $301$ redirects when you change product or page URLs, but for manual redirects:

1. Go to Online Store → Navigation → URL Redirects
2. Click "Create URL redirect"
3. Enter the old path (e.g., /old-product) and new destination
4. Save

For server errors, contact Shopify support, as server configuration is managed by Shopify.

For Next.js:

Implement redirects in next.config.js:

module.exports = {
  async redirects() {
    return [
      {
        source: '/old-page-url',
        destination: '/new-page-url',
        permanent: true, // 301 redirect
      },
      {
        source: '/old-directory/:path*',
        destination: '/new-directory/:path*',
        permanent: true,
      },
    ];
  },
};

For server errors, check your Node.js application logs and ensure all dependencies are installed and API routes are functioning.

5. Update Internal Links and Sitemaps

After fixing redirects or removing pages:

Update internal links: Search your site for any links pointing to the old URL and update them to point directly to the new destination
Update XML sitemaps: Remove deleted URLs from your sitemap and ensure it only includes live, accessible pages
Submit updated sitemap to Google Search Console: This helps Google discover the changes faster

6. Verify and Monitor

After implementing fixes:

Test URLs manually: Visit each fixed URL in a browser to confirm it loads correctly or redirects properly
Use Zignalify's re-audit feature: Trigger a fresh audit to verify the page no longer flags for error status codes
Check Google Search Console: Monitor the Coverage report to ensure errors are decreasing and indexed pages are increasing
Set up monitoring alerts: Use uptime monitoring tools like UptimeRobot or Pingdom to alert you immediately if pages return error codes in the future

Best Practices

Implement Custom 404 Pages with Navigation: When $404$ errors are unavoidable (user typos, outdated external links), ensure your $404$ page provides value by including site search, popular pages, category navigation, and a clear path back to functional content. A helpful $404$ page reduces bounce rate and keeps users engaged despite the error.
Use $301$ Redirects for Permanent Changes Only: Reserve $301$ Moved Permanently for pages that will never return to the old URL. Use $302$ Found or $307$ Temporary Redirect for short-term redirects (A/B tests, seasonal campaigns) that you plan to revert. Incorrect use of $301$ can cause crawlers to drop the old URL from indexes prematurely.
Avoid Redirect Chains Longer Than One Hop: Every redirect adds latency and dilutes link equity. If URL A must redirect, send it directly to the final destination, not through intermediate URLs. Periodically audit your redirects to identify and collapse chains (e.g., A → B → C should become A → C).
Monitor Server Health and Uptime Proactively: Use uptime monitoring services to catch $5xx$ errors immediately before they impact many users or waste crawl budget. Set up alerts for sustained downtime, slow response times, or repeated server errors. Address hosting capacity issues before traffic spikes overwhelm your server.
Regularly Audit for Broken Internal Links: Use tools like Screaming Frog, Ahrefs, or Zignalify's cross-page checks to identify internal links pointing to $404$ errors. Fix these by updating links to point to active pages or removing references to deleted content. Cleaning up internal links improves crawl efficiency and user experience.
Submit Updated Sitemaps Promptly: Whenever you delete pages, implement redirects, or fix errors, regenerate your XML sitemap and resubmit it to Google Search Console. This signals that your site structure has changed and prompts faster re-crawling of affected URLs.

FAQs

Q: Should I redirect all $404$ errors or let some remain as $404$s?

Not every $404$ needs a redirect. If the page was deleted because it's outdated, irrelevant, or low-quality, and no suitable replacement exists, let it return a proper $404$. This tells search engines the page is intentionally gone. Only implement $301$ redirects when a logical replacement exists or when the page has valuable backlinks or traffic that should be preserved. Over-redirecting (especially redirecting everything to the homepage) creates poor user experience and confuses search engines.

Q: How do I fix redirect chains?

Use tools like Screaming Frog, Redirect Checker, or browser developer tools (Network tab) to trace redirect paths. If you find a chain (A → B → C), update the redirect rule for A to point directly to C, eliminating intermediate hops. In .htaccess or nginx.conf, simply change the destination URL for the first redirect. Then clear server and CDN caches to ensure the change takes effect immediately.

Q: Why does Google Search Console show $404$ errors for URLs I never created?

These are often caused by user typos, automated bot scans, hacked URLs appended to your domain, or outdated links from external sites. If these URLs never existed and have no backlinks or traffic, you can safely ignore them, Google won't penalize you for $404$ errors on URLs you didn't create. Focus on fixing $404$s for URLs that were previously indexed, have backlinks, or receive referral traffic.