Hocam öncelikle bunu bir dener misiniz?
Hata mesajını gizliyor bu.

I made an account just to give the solution.
Go to the function.php file and go to line 5323.
Do you see there (or above) that this command?
if ( WP_DEBUG && apply_filters( ‘deprecated_function_trigger_error’, true )
set it to “false”
Hope it helps!