Emails are not arriving

Good afternoon, emails sent from the course task to education@simpleone.ru have stopped arriving; I only see error emails and emails from other users (from other setups). Platform version 1.31.

Hello, colleagues from the Training Center, someone will contact you regarding the email module.
Have a nice day.

Hello, due to the high workload caused by intensive writing training, responses may be delayed. We will monitor the situation.