A 500 error is the web server reporting that something failed without saying what. Work through these in order.
1. Check the error log
cPanel → Metrics → Errors shows the most recent entries, which usually name the file and line. This step saves the most time.
2. Rename .htaccess
A corrupt rewrite rule is the most common cause. In File Manager rename public_html/.htaccess to .htaccess-old and reload. If the site returns, log in and go to Settings → Permalinks and click Save to write a clean file.
3. Deactivate plugins
Rename wp-content/plugins to plugins-off and test.
4. Increase the memory limit
Set memory_limit to 256M in MultiPHP INI Editor.
5. Check the PHP version
A theme or plugin that is incompatible with your PHP version can throw a 500 on every request. Switch back one version in MultiPHP Manager and test.
6. Check file permissions
Folders should be 755, files 644. Anything set to 777 will be rejected outright by the server.
If none of this resolves it, open a ticket quoting the exact timestamp of the error so we can match it against the server logs.
