Mail letters are sent without problems, but they do not work, what should I do?

Question

Mail server

letters are sent to some mail addresses without problems, but the problem is not received in SMTP, the mail is kept by the yandex server, here is the error code 550 Please turn on SMTP Authentication in your mail client. mail-ot1-f50.google.com[209.85.210.50]:46146 is not permitted to relay through this server without authentication.
help what to do?

Answer 1

The problem is solved because I wrote the yandex support service and they updated the domain settings and everything worked