WordPress 500 Internal Server Error: Diagnosis and Fix

What this problem is

Your WordPress site returns 500 Internal Server Error on the frontend, wp-admin, or both.

Why it happens (common causes)

• Fatal PHP error (plugin/theme/core)
• Broken or incompatible .htaccess rules
• PHP limits: memory or execution time
• Server misconfiguration after a change/migration

Prerequisites

• FTP/File Manager access
• Access to server error logs (highly recommended)

Diagnosis

1. Confirm it is a 500 and note if it affects only wp-admin or all pages.
2. Check the server error log and PHP log for the first fatal error.

Detailed steps

Step 1) Check error logs

Look for a plugin/theme path or memory/timeouts.

Step 2) Reset .htaccess (Apache)

Rename .htaccess to .htaccess.bak and retest. Then regenerate permalinks in WordPress once you regain access.

Step 3) Disable plugins and switch theme

• Rename wp-content/plugins to disable plugins
• Switch to a default theme by renaming the active theme folder

Step 4) Increase PHP limits

Increase memory and execution time in the hosting panel.

Expected results

• 500 error disappears
• You identify the exact cause from logs

What to do if it fails

• If 500 persists with plugins disabled and default theme, re-upload WordPress core
• Ask hosting support to provide the full error log line and stack trace

Best practices

• Keep backups and test changes on staging
• Monitor logs after updates