Mail forwarding from your domains on your server to gmail and ukr.net

There is a server running Ubuntu 22.04 + ISPManager 6 + ClamAv 0.103.11+dfsg-0ubuntu0.22.04.1, Dovecot 1:2.3.16+dfsg1-3ubuntu2.2, Exim 4.95-4ubuntu2.6, SpamAssassin 3.4.6-1ubuntu0.22.04.1, sieve 1:2.3.16+dfsg1-3ubuntu2.2

It is necessary to configure several mail domains (with DMARC/SSL) using the ISPManager panel itself, so that all mail from these domains is forwarded to other emails on public services (gmail.com, ukr.net, etc.).

Recently, a migration was carried out from the old server to the new one (the domains remained the same) and everything worked fine on the old server.

We tried to configure it ourselves, but there was a problem that Gmail does not accept such emails due to the low reputation of the sending domain:

SMTP error from remote mail server after pipelined end of data:

Gmail has detected that this message is likely suspicious due to the very low reputation of the sending domain. To best protect our users from spam, the message has been blocked. For more information, go to https://support.google.com/mail/answer/188131