How to configure MTA so that mail goes to the addressee?

Question

Exim

As a result of the last question (setting up mail on my domain), I decided to raise my MTA (postfix) + MDA and a problem arose: letters arrive normally, leave normally (250 OK), but when they leave, they don’t even appear on the incoming side in spam.
Everything is fine in the logs
Configured Reverse DNS, TLS, DMARC (v=DMARC1; p=none; sp=none; rua=mailto:[email protected]).
Where should I look to sort out the problem?
As I understand it, a paid relay can solve a similar problem, but I would like to figure it out on my own.

Answer 1

Most likely your IP address (and possibly the entire Range ISP) allocated by IPS is in the DNSBL blacklists.
Check here: https://www.dnsbl.info/

Answer 2

put monitoring it will be easier to manage https://easydmarc.com