You clicked a link, hit refresh, or submitted a form (and instead of the page you expected, you got a stark, unhelpful message): 500 – Internal Server Error. No explanation. No guidance. Just a wall of digital nothing telling you something went wrong, somewhere, somehow.
Unlike the 404 (which at least tells you a specific page couldn’t be found), the 500 error is a catch-all. It’s the server throwing its hands up and saying “something broke on my end, and I’m not entirely sure what.” For visitors, it’s frustrating. For webmasters, it can be genuinely alarming. And for SEO, a server that regularly returns 500 errors is quietly bleeding ranking potential every single day it goes unaddressed.
Let’s get into exactly what a 500 error is, what causes it, how to diagnose and fix it, and why it’s one of the most damaging technical issues a site can suffer from an SEO perspective.
What Is a 500 Internal Server Error?
The 500 status code is part of the 5xx family of HTTP response codes, which are all server-side errors. Where the 4xx codes (like the 404) indicate the client made a bad request, 5xx codes indicate the server itself failed to fulfil a perfectly valid request. The client did everything right. The server just couldn’t deliver.
The 500 specifically is the generic fallback in the 5xx family. When a server encounters an unexpected condition that prevents it from completing a request (and that condition doesn’t fit into one of the more specific 5xx codes), it returns a 500. Think of it as the server’s way of logging a crash without having enough information to be more specific about what crashed.
Other 5xx codes are more descriptive (501 means Not Implemented, 502 means Bad Gateway, 503 means Service Unavailable, 504 means Gateway Timeout), but a 500 is the bluntest instrument in the group. It knows something went wrong. It just doesn’t know how to articulate it beyond that.
Why Does It Happen?
The causes of a 500 error are wide-ranging, which is part of what makes it such a headache to diagnose. Here are the most common culprits.
Broken or misconfigured .htaccess files are one of the leading causes, particularly on Apache servers. The .htaccess file is incredibly powerful (it controls redirects, rewrites, access rules, caching headers, and more), but a single syntax error can bring the entire site down with a 500. Adding a redirect rule with a typo, copying an incompatible snippet from a tutorial, or uploading a malformed file are all common triggers.
PHP errors and fatal script failures are another frequent cause. If a PHP script encounters an unhandled exception, calls a function that doesn’t exist, runs out of memory, or hits a timeout, the server may return a 500 rather than attempt to render a broken page. This is especially common after a plugin update, a CMS upgrade, or a custom code change that introduced a bug.
Permission errors on files or directories can also trigger a 500. Web servers expect specific permission settings on files and folders. If a file that needs to be executed is set to the wrong permission level (either too restrictive or, in some cases, too permissive), the server may refuse to process it and return a 500 instead.
Database connection failures are a common cause for CMS-driven sites like WordPress, Joomla, or Drupal. If the database server is down, the credentials in the config file are wrong, or the database has hit its connection limit, the CMS can’t retrieve the data it needs to render the page and the result is often a 500.
Exhausted server resources (RAM, CPU, or process limits) can push a server past its threshold under high traffic or after a resource-intensive process runs unchecked. Shared hosting environments are particularly vulnerable here, as resource caps are often tightly constrained.
Corrupted or incompatible plugins and themes are a major cause on WordPress sites specifically. A plugin that hasn’t been updated to work with the latest PHP version, or two plugins with conflicting code, can throw a fatal error and return a 500 to every visitor trying to load the affected pages.
The SEO Damage a 500 Error Causes
If a 404 is a slow leak for your SEO, a 500 is a burst pipe. Here’s why.
When Googlebot or any other search engine crawler visits a URL and receives a 500 response, it doesn’t immediately drop the page from the index. It knows servers have bad days. But if it returns repeatedly and keeps receiving a 500, it will eventually begin treating that URL as unavailable and pull it from the index. For pages that have taken months or years to rank, that’s catastrophic.
The crawl budget problem is more acute with 500s than with 404s. A 404 tells the crawler the page is gone and to move on. A 500 is ambiguous (the page might come back). Crawlers may revisit 500 URLs more aggressively in the short term hoping for recovery, burning crawl budget on pages that are delivering nothing.
There’s also the indexing continuity problem. If your homepage or key landing pages are intermittently returning 500s (even for short windows during peak traffic or after a botched deployment), you risk those pages being served from a stale cache or temporarily deindexed. Google Search Console will log these errors, and a pattern of them signals to Google that your site is unreliable.
Server reliability is an indirect but real ranking factor. Google has been explicit that page experience, including availability and speed, matters. A site that throws 500 errors regularly is not providing a good page experience, and that will eventually show up in rankings.
User trust takes a hit too. A visitor who lands on a 500 page (especially from a paid ad or an email campaign) is unlikely to try again. Bounce rates spike, conversion rates collapse, and any goodwill you’d built with that traffic is gone.
How to Diagnose a 500 Error
Before you can fix it, you need to find it. Here’s how to approach the diagnosis.
Check your server error logs first. This is always step one. Your hosting control panel (cPanel, Plesk, or your server’s native logging system) will have access logs and error logs. The error log will almost always contain the specific line that triggered the 500, including the file name, the line number, and the nature of the error. If you’re on a managed host, you may need to ask support for log access.
Enable error display temporarily on a development environment. If you can replicate the issue in a staging or local environment, enabling verbose PHP error display will surface the exact error message that the server is suppressing in production. Never enable error display on a live site (it can expose sensitive server information to visitors and attackers).
Isolate the .htaccess file. If your site went down immediately after a change to .htaccess, rename the file temporarily to something like .htaccess_old. If the site comes back up, the .htaccess was the culprit. Restore it line by line until you identify the bad rule.
Deactivate plugins one by one. On WordPress, if you can still access the admin panel, deactivate all plugins and reactivate them one at a time to identify the conflict. If you can’t access the admin panel, rename the plugins folder via FTP or your file manager (WordPress will then see no plugins and disable them all automatically).
Check file permissions. PHP files typically need 644 permissions, and directories typically need 755. Anything wildly outside those values should be corrected. Your hosting provider or a server admin can verify what the correct permissions should be for your specific setup.
Test your database connection. For CMS-driven sites, verify that your database credentials in wp-config.php (or the equivalent config file for your CMS) are correct and that the database server is responding. Your host’s control panel can usually tell you whether the database service is running.
What Webmasters Can Do to Prevent 500 Errors
Prevention is always better than scrambling to fix a live outage. Here are the habits and configurations that keep 500s from happening in the first place.
Stage all changes before pushing to production. Whether it’s a plugin update, a PHP version upgrade, a theme change, or a custom code edit, test it in a staging environment first. Most quality hosting providers offer one-click staging environments. Use them.
Keep software updated but test updates before applying them live. Outdated plugins, themes, and CMS versions introduce vulnerabilities, but untested updates introduce instability. The solution is a staging-first update workflow, not avoiding updates altogether.
Back up before every significant change. A full site backup (files and database) before any update or code change means that if a 500 does occur, you can roll back within minutes rather than spending hours trying to debug a broken production site.
Set up uptime monitoring. Services like UptimeRobot, Pingdom, or StatusCake will alert you the moment your site returns anything other than a 200 OK. Knowing about a 500 within seconds rather than discovering it hours later when someone mentions it can be the difference between a minor incident and a serious ranking hit.
Configure a meaningful custom 500 error page. Just like a custom 404, a custom 500 page won’t fix the underlying problem (but it will give visitors something more useful than a blank server error). Include a brief explanation, a link to your homepage, and a way to contact you. It won’t prevent the SEO impact, but it reduces the user experience damage.
Monitor Google Search Console consistently. The Pages report and the Coverage section in GSC will surface any 5xx errors Google has encountered on your site. If you see a spike in server errors, investigate immediately. Don’t wait for rankings to drop before you act.
Talk to your host about resource scaling. If your 500s are being caused by resource exhaustion under load (common on shared hosting), it may be time to upgrade your hosting plan, move to a VPS or dedicated server, or implement caching to reduce the server load generated by each request.
A Final Word
The 500 Internal Server Error is the web’s most honest admission that something has gone badly wrong behind the scenes. It’s vague by design (because the causes are so varied), but that vagueness is exactly what makes it so important to investigate quickly and thoroughly. Every minute a 500 is live is a minute crawlers can’t index your content, visitors can’t access your site, and your rankings are quietly eroding.
Technical SEO (the unglamorous, under-the-hood work of keeping a site healthy, fast, and accessible) is what separates sites that hold their rankings long-term from those that inexplicably slide after a messy deployment or an overlooked server issue. If you want a complete, systematic framework for handling not just error codes but the full spectrum of technical and on-page SEO factors across every major search engine (Google, Bing, Yandex, Baidu, DuckDuckGo, Snipesearch, YaCy, and more), SEO Fundamentals is the resource we recommend. Built on over two decades of real-world server management, web development, and digital marketing experience, it covers .htaccess configuration, redirect strategy, sitemap and robots.txt structure, Core Web Vitals, mobile-first indexing, and multi-engine optimisation in one thorough, no-fluff guide. If your site has ever thrown a 500 and you weren’t sure where to start, this book gives you the foundation to make sure it doesn’t happen again (and the toolkit to handle it fast when it does).
