Has your mail server been hacked> Reports an internal error on POP3 accounts. And the server response text is in Cyrillic language?
Task '[email protected] - Sending' reported error (0x800CCC6A) : 'Your outgoing (SMTP) email server has reported an internal error.
If you continue to receive this message, contact your server administrator or Internet service provider (ISP).
The server responded: Cyrillic text'