How to set up domain for mail on debian 10?

Question

Debian

Good afternoon! Available:
1) Domain registered on godaddy (NS digitalocean registered)

2) Server on digitalocean (Debian 10.5 with Fastpanel), domain added in Networking DO section.

3) Fastpanel in the mail section, a domain is attached and a box of the form [email protected] domain is created, when I enter roundcube, I receive mail to this box, but I cannot send it. I am getting an error like:

Reporting-MTA: dns; yanik

Action: failed
Final-Recipient: rfc822;***@gmail.com
Status: 5.0.0
Remote-MTA: dns; gmail-smtp-in.l.google.com
Diagnostic-Code: smtp; 550-5.7.28 [server ip here 1] Our system has detected an unusual rate of
550-5.7.28 unsolicited mail originating from your IP address. To protect our
550-5.7.28 users from spam, mail sent from your IP address has been blocked.
550-5.7.28 Please visit
550-5.7.28 https://support.google.com/mail/?p=UnsolicitedIPError to review our
550 5.7.28 Bulk Email Senders Guidelines. e12si12745857wrd.246 - gsmtp

As I understand it, you need an MX record or something else, how to set it up correctly, please tell me.

Answer 1

Good afternoon!
Needed:
MX-record, although it is very strange, it is she who is responsible for receiving, and you write what mail you receive,
SPF, DKIM, DMARC records
correspondence to HELO and rDNS
In general, it is best to test, for example, through mail tester