Do not receive letters to your mail server from STEAM, why?

Question

postfix

Deployed postfix, checked the availability of mailboxes through services such as mail/gmail/yandex letters reach.
But when registering through steam, letters do not come, the log is empty.
Where to dig?

Answer 1

If the log is empty, then there is essentially nothing to dig, mail simply doesn’t reach your server ... All you have to do is write to Steam support, but I’m not sure what success awaits here.

Answer 2

There are several options, I'll start with the last one:
1. Letters arrive at the server, but are rejected by postfix. Read /var/log/maillog to understand. You can use tail -f to immediately send and see what happens.
2. Letters do not arrive at the server due to incorrect DNS entry / cache settings, etc. Check again (including using dig and sending test emails).
3. Emails are not sent to the specified domain for some reason. You can temporarily bind the Google / Yandex mail service and check the receipt.
4. Letters must not be sent by Steam. Change your account settings and check