А что у студофиса с почтой? Я написал, а там такое:
Final-Recipient: utf8-addr;
📧so@itmo.ruAction: failed
Status: 5.6.7
Remote-MTA: dns;
emx.mail.ru. (
217.69.139.180, the server for the domain
itmo.ru.)
Diagnostic-Code: smtp; local-part of envelope RCPT address contains utf8 but remote server did not offer SMTPUTF8
Last-Attempt-Date: Thu, 20 Aug 2020 02:40:51 -0700 (PDT)