500 Internal Server Error: What Causes It and How to Fix It

A "500 Internal Server Error" is one of the least helpful messages on the internet — it just means "something broke on the server," with no detail about what. That vagueness is deliberate (servers don't want to leak internal details to visitors), but it means diagnosing the real cause takes a bit of detective work.

The most common causes

• A plugin or theme conflict. By far the most common cause on WordPress — two plugins fighting over the same function, or a plugin that's incompatible with your current PHP version.
• A corrupted .htaccess file. A bad rewrite rule or a stray character in .htaccess will take the whole site down with a 500 error, especially right after installing a new plugin that modifies it.
• Exhausted PHP memory limit. If a page (or a plugin running in the background) tries to use more memory than the server allows, PHP gives up and the server returns a 500.
• File permission errors. Core files or folders with the wrong permissions (often after a manual upload or a botched migration) can be unreadable to the web server process.
• A PHP version mismatch. Code written for an older PHP version can throw fatal errors on a newer one (or vice versa) after a hosting-side PHP upgrade.

How to actually find out which one it is

Guessing is what turns a 15-minute fix into a multi-day ordeal. The fastest real diagnostic path is:

• Check your host's error log (usually in cPanel, or via SSH) — PHP almost always logs the real fatal error there even though the visitor only sees "500."
• Temporarily rename your .htaccess file — if the site comes back, the problem is in there.
• Deactivate all plugins (via file manager/FTP if you can't reach wp-admin) and reactivate them one at a time until the error returns.
• Try bumping memory_limit in wp-config.php or php.ini as a temporary test, not a permanent fix — if it resolves the error, something is genuinely leaking memory and needs to be found.

If you'd rather skip the trial-and-error, this is exactly the kind of issue we fix through our 500 error repair service — we read the actual server logs, find the real cause, and give you one fixed-price quote before touching anything. You only pay once the site is confirmed working again.