How to set up sending and receiving mail in iRedMail?

Question

Email

Deployed the iRedMail mail server on CentOS 7.
On the local network, mail comes and goes, but there is no connection with external addresses.
On the hosting site, in the DNS hosting section, I created an A-record with the name mail and the ip-address of the router (which is the DNS server and gateway).
I also specified the mail.mydomain.ru MX record in the DNS hosting. (it was automatically renamed simply to mail).
Created TXT records "dkim._domainkey" obtained using the command "amavisd -c /etc/amavisd/amavisd.conf showkeys", and the record "@" in which indicated "v=spf1 ip4: (ip_router) -all".
I also opened port 143 on the router for the mail server.
При отправке сообщения на адреса моего домена выходит ошибка: Message was not accepted -- invalid mailbox. Local mailbox [email protected] is unavailable: user not found
А на сервере в логе /var/log/maillog, при отправке сообщений идёт ошибка:
Feb 6 21:40:48 mail postfix/qmgr[2659]: AE3E5180E9AC6: from=, size=1639, nrcpt=1 (queue active)
Feb 6 21:41:08 mail postfix/smtp[21624]: AE3E5180E9AC6: to=, relay=none, delay=76056, delays=76036/0.05/20/0, dsn=4.4.3, status=deferred (Host or domain name not found. Name service error for name=gmail.com type=MX: Host not found, try again)
Так же, если выполнять "nslookup -type=txt dkim._domainkey.mydomain.ru", то выдаётся следующее:
Не заслуживающий доверия ответ:
dkim._domainkey.mydomain.ru text =
""v=DKIM1; = p ""
"" VicCvZVCVCvcuHENEczPZVZIVuEECICdZUCziUZCIZCjcvzvoz / CZiczCczcicZC ""
"" ZczczcZUCZciuzciZVZIUvzVZVzvoizvozkvkDOvkdvodvodvkdvodv / CCxxZZxz ""
"" 9zvz8v34zvzvuiudidziduddddiuddivdivkdvidvidikdkkkHHUHczvZiVzVZvj ""
"" IZVUvzu8e384u34vzZvzvzvj "" Looking
for something to do on the server to send? For reception, I did not specify something correctly, maybe? Or do you need to specify something else?

Answer 1

Port 143 is the client port for IMAP mail collection.
Mail between servers is delivered on the 25th port. I do not see in the description that you would open it.
Although the bounce message "Message was not accepted -- invalid mailbox. Local mailbox [email protected] is unavailable: user not found", clearly indicates that the connection took place, but the server rejected the incoming letter to [email protected] - with resolution - the user does not exist. I would double check that the address really exists, i.e. the server is waiting for a letter to this address.