Hello Alex,
Can you enable debug mode in your WP and check the debug.log when Defender stops?
To enable it, open your wp-config.php file and look for define(‘WP_DEBUG’, false);. Change it to:
define('WP_DEBUG', true);
In order to enable the error logging to a file on the server you need to add yet one more similar line:
define( 'WP_DEBUG_LOG', true );
In this case the errors will be saved to a debug.log log file inside the /wp-content/directory.
Depending on whether you want your errors to be only logged or also displayed on the screen you should also have this line there, immediately after the line mentioned above:
define( 'WP_DEBUG_DISPLAY', false );
The wp-config.php is located in your WordPress root directory. It’s the same file where the database configuration settings are. You will have to access it by FTP or SFTP in order to edit it.
We would need then to see content of the debug.log file – so please upload it to service like a Dropbox and paste link here.
kind regards
Kasia
