Why doesn't hMailServer accept external emails?

Question

Mail server

Hi all!
I installed hMailServer + Thunderbird client + SSL on my home computer and set up the server. For a while everything worked and letters were sent and received.
Something went wrong (I probably broke something) and now the mail works like this:
1) letters from the home server are sent and reach the same server
2) letters from hMail are delivered to google, mail
3) letters from google, mail do not come to my mail

Mail.ru gives the following answer:
This letter was created automatically by the Mail.ru server, you do not need to respond to it.

Unfortunately, your email could not be delivered to one or more recipients:
[email protected] (hidden address, replaced it with xxx)
retry timeout exceeded
We recommend that you check the correctness of the recipient addresses.

There are similar problems on the network and someone even managed to solve the problem, but I still could not understand what was not working and how to fix it. Ran this test: https://mxtoolbox.com/
Received the following diagnostic information:
! SMTP Reverse DNS Resolution Reverse DNS Resolution - No PTR Record found More Info
! SMTP TLS Warning - Does not support TLS. More info
! SMTP Transaction Time 15.190 seconds - Not good! on Transaction Time More Info
+ SMTP Connection Time 0 seconds - Good on Connection time
+ SMTP Open Relay OK - Not an open relay.

C PTR seems to be understood, it is not yet available.
TLS Warning - Does not support TLS <<<< The entry says I don't have an SSL certificate?

More Information About Smtp Tls
Your SMTP email server does advertise support for TLS. After connecting to your mail server we issue an EHLO command to introduce ourselves and to request that your server announce which commands and protocols it supports. Your server's response did not include "250-STARTTLS" indicating TLS support.

Additional Information
TLS stands for Transport Layer Security and allows email servers to exchange emails over an encrypted connection using the same type of mechanism as HTTPS uses to secure websites. In all but a few cases, you should still be able to send and receive email but your messages will be transmitted in plain text without TLS encryption.

What could be the problem with the server?

Answer 1

Google sent a reply too:

The response was:
The recipient server did not accept our requests to connect. Learn more at https://support.google.com/mail/answer/7720 [mx.mysite.blog. xxx.xxx.xxx.xx: unable to read banner]

I contacted the domain name provider and asked to check the mx-record. The specialist said:
MX-record is returned correctly:
dig xxx.xxmx +trace
;; ================================================= =============================
;; ASK FROM [8.8.8.8] ABOUT [.]
;; ================================================= =============================
; <<>> Net::DNS::Dig 0.12 <<>> -t ns .
;;
;; got an answer.
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4672
;; flags: qr rd ra; QUERY: 1, ANSWER: 13, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;. IN NS
;; ANSWER SECTION:
. 34080 IN NS j.root-servers.net.
. 34080 IN NS k.root-servers.net.
. 34080 IN NS a.root-servers.net.
. 34080 IN NS b.root-servers.net.
. 34080 IN NS g.root-servers.net.
. 34080 IN NS d.root-servers.net.
. 34080 IN NS l.root-servers.net.
. 34080 IN NS i.root-servers.net.
. 34080 IN NS f.root-servers.net.
. 34080 IN NS m.root-servers.net.
. 34080 IN NS e.root-servers.net.
. 34080 IN NS c.root-servers.net.
. 34080 IN NS h.root-servers.net.
;; Query time: 20ms
;; SERVER: 8.8.8.8# 53(8.8.8.8)
;; WHEN: Tue Apr 19 22:49:20 2022
;; MSG SIZE rcvd: 228 -- XFR size: 14 records
;; ================================================= =============================
;; ASK FROM [j.root-servers.net] ABOUT [blog.]
;; ================================================= =============================
; <<>> Net::DNS::Dig 0.12 <<>> -t ns blog.
;;
;; got an answer.
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4672
;; flags: qrrd; QUERY: 1, ANSWER: 0, AUTHORITY: 4, ADDITIONAL: 8
;; QUESTION SECTION:
;blog. IN NS
;; AUTHORITY SECTION:
blog. 172800 IN NS a.nic.blog.
blog. 172800 IN NS b.nic.blog.
blog. 172800 IN NS c.nic.blog.
blog. 172800 IN NS d.nic.blog.
;; ADDITIONAL SECTION:
a.nic.blog. 172800 IN A 194.169.218.94
b.nic.blog. 172800 IN A 185.24.64.94
c.nic.blog. 172800 IN A 212.18.248.94
d.nic.blog. 172800 IN A 212.18.249.94
a.nic.blog. 172800 IN AAAA 2001:67C:13CC:0:0:0:1:94
b.nic.blog. 172800 IN AAAA 2A04:2B00:13CC:0:0:0:1:94
c.nic.blog. 172800 IN AAAA 2A04:2B00:13EE:0:0:0:0:94
d.nic.blog. 172800 IN AAAA 2A04:2B00:13FF:0:0:0:0:94
;; Query time: 3ms
;; SERVER: 192.58.128.30# 53(j.root-servers.net)
;; WHEN: Tue Apr 19 22:49:20 2022
;; MSG SIZE rcvd: 266 -- XFR size: 13 records
;; ================================================= =============================
;; ASK FROM [a.nic.blog] ABOUT [xxx.blog.]
;; ================================================= =============================
; <<>> Net::DNS::Dig 0.12 <<>> -t ns xxx.blog.
;;
;; got an answer.
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4672
;; flags: qrrd; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 0
;; QUESTION SECTION:
;xxx.blog. IN NS
;; AUTHORITY SECTION:
xxx.blog. 3600 IN NS ns1.reg.ru.
xxx.blog. 3600 IN NS ns2.reg.ru.
;; Query time: 37ms
;; SERVER: 194.169.218.94# 53(a.nic.blog)
;; WHEN: Tue Apr 19 22:49:20 2022
;; MSG SIZE rcvd: 74 -- XFR size: 3 records
; <<>> Net::DNS::Dig 0.12 <<>> -t mx xxx.blog.
;;
;; got an answer.
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4672
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;xxx.blog. IN MX
;; ANSWER SECTION:
xxx.blog. 3600 IN MX 0 mx.xxx.blog.
;; Query time: 3ms
;; SERVER: 194.58.117.17# 53(ns1.reg.ru)
;; WHEN: Tue Apr 19 22:49:20 2022
;; MSG SIZE rcvd: 51 -- XFR size: 2 records
Still trying to figure out what's wrong with mx