only for developers (not recommended on live site)
Debug mode is only for developers or can used to track the errors like woosh something went wrong.
It will be great if you send me screen shot of this page, when contacting me via mail about any trouble.
Login to your FTP account
Visit app/config/app.php
Change
'debug' => FALSE,
to
'debug' => TRUE,
Save the file, and now site will display proper error reporting.