When attempting to send an email that contains UTF-8 characters the following error is observed:

email address local or domain part contains UTF-8 character: χρήστης@παράδειγμα.ελ

The same issue appears on frontend side in Zabbix 6.4 (since the Email providers dropdown was added to Email media type form).

Emails that contain non-latin UTF-8 characters are perfectly valid emails and, therefore, must pass validation on frontend and must be properly handled by the server.

Please add support for UTF-8 characters in Email parameter, since such email addresses as χρήστης@παράδειγμα.ελ are completely valid email addresses.