Where do the letters disappear and do not reach the addressee?

Question

postfix

Hey!
I wanted to make a notification with sending me a soap that someone came in via ssh
letters come only to Gmail - Yandex, Mail - zero reaction - not in spam, not anywhere. As if it never happened.
In the mail queue, in the logs of the mailer - nothing, where to dig?
Maybe there is an analogue of path tracing but for mail programs?
It also does not happen that strict Gmail accepts mail without problems and our mailers do not ...
PS it's good that they didn't start sending applications from the site through their mailer .... : -(

Answer 1

You need to look at the logs of the mailer from which you send. If there is a transfer complete 200 (or 220) at the end, then everything is OK and there are problems on the receiving side.

Answer 2

Usually the problem is in the spf-record https://rigweb.ru/support/servisy-dlya-pochty/kak-...
After setting it up, Yandex starts accepting ... into the spam folder))))