Adding at alias/email address with @ symbol in the local part causes error

[NicoloLazzaroni]

Hello,

PostfixAdmin does not check if a user adds a second @ in the localpart of the email address.

If the user does it for an email account then the system pops up with the error: Regex check failed.

Eg. Regex check failed for test@abc.eu@abc.eu

I could solve it by adding this code in the functions.php file, inside the function "check_email":

    if (substr_count($ce_email,"@") != 1) {
       return sprintf("Please, do not insert the '@' (at) symbol.", htmlentities($email));
    }

    if (substr_count($email,"@") != 1) {
       return sprintf("Please, do not insert the '@' (at) symbol.", htmlentities($email));
    }

The main issues, however, happens with the aliasses:
If the user adds a second @ in the local part, unless after the "at" symol there is the same domain name of the chosen domain, PA produces a 500 error in the console and a blank page. The check I added is not run so the problem is before the call to check_email.

Thank you for your time.

Regards,
NL