Mail server name error

If you have sent a message to a Yandex address and received a non-delivery report that states the following: “EHLO requires domain address”, “HELO requires domain address”, this means that the mail server specified its name incorrectly when trying to send your message. This error may be returned when invalid characters are used in the system name of the sender's computer in accordance with RFC 2821 and RFC 1045 standards.

Contact your system administrator or your mail service support team.