By default the display_errors option on shared hosting is set to Off, i.e. error display is disabled.
Sometimes for debugging the site/cms you need to see what kind of error, why the site gives out code/error 500, white screen, etc. For this purpose it is necessary to switch on displaying of errors on the screen for debugging time, for this purpose:
Go to "Software → Editor MultiPHP INI "
Select the domain to edit and set display_errors to On.
Press "Apply " to save the settings.
On the same screen you can also change "Basic PHP INI Settings "
Now you will be able to see the errors on the screen when you open your site or a specific page in the browser.
Enable this option (display_errors) only for the time of debugging the site (CMS, errors on the site), after completion be sure to disable it.