Hi @keywon,
Sorry to know that you are experiencing this issue.
Could you please verify if the issue is resolved after deactivating Hummingbird?
To investigate the issue further, can you please enable WP_DEBUG_LOG and check if a PHP error is being reported?
To enable WP_DEBUG_LOG, please add the following define statements in the wp-config.php file.
define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', true );
define( 'WP_DEBUG_DISPLAY', false );
Once the above code is added, please replicate the issue. The debug.log file is usually located in the wp-content directory of your WordPress installation. You can access it via FTP, SSH, or your hosting file manager. The file is named debug.log. Please share the debug.log file using Google Drive or DropBox in your next response so that we can help you further.
I hope the following guide comes in handy: https://developer.www.ads-software.com/advanced-administration/debug/debug-wordpress/
Kind Regards,
Nebu John