Error

Hello,

We apologize for the issue you are facing with the theme customizer after installing the Rank Math plugin. The critical error and the 500 error code you are encountering could be due to a conflict between Rank Math and your theme or another plugin.

To troubleshoot this issue, we recommend the following steps:

1. Check for Plugin Conflicts: Deactivate all other plugins except Rank Math and see if the customizer works. If it does, reactivate the plugins one by one to identify which one is causing the conflict.

2. Switch Themes Temporarily: If deactivating other plugins does not resolve the issue, try switching to a default WordPress theme (like Twenty Twenty-One) to see if the problem persists. This can help determine if the issue is with your current theme.

3. Enable Debugging: You can enable debugging in WordPress to get more detailed error messages. To do this, add the following lines to your wp-config.php file:

   define( 'WP_DEBUG', true );
   define( 'WP_DEBUG_LOG', true );
   define( 'WP_DEBUG_DISPLAY', false );

   After enabling debugging, check the wp-content/debug.log file for any errors that might provide more insight into the issue.

4. Check Server Logs: Sometimes, server logs can provide additional information about what might be causing the 500 error. You can check with your hosting provider for access to these logs.

If these steps do not resolve the issue, please reply to this ticket, and a human agent from the Rank Math Support team will assist you further. Thank you for raising this concern!

Sources:
Fatal Error Happening on Some Installations After 1.0.49 Update » Rank Math