Vesta CP — why do emails end up in spam after a clean installation?

Question

Email

After a clean installation of Vesta CP on a new VPS, and with a further call to the PHP mail() function, the letters end up in spam. Tested on boxes - Gmail, mail, yandex. There is only water
in the network. Surely the problem is not unique and this is a known bug (oversight). Has anyone come across and have a solution?

Answer 1

It is necessary to configure mail authorization (communication with the mail server). It is critical that the letter is sent from the mail server. It is necessary to configure the mail server correctly. (I use the SMTP protocol).
The fact is that now mail servers check the sender, if they see that something is wrong, they send him a request; If you are a mail server, resend your letter . and in such cases, your letter will be discarded or fall into spam. This is just one example of checking mail...
There are times when your mail server should have the following configured:
DNS records (MX,A,SPF,DKIM)
Reverse DNS (PTR records)
You should also check your IP in spam databases

Answer 2

correctly configure the mail server, specify dkim, dmarc in dns.