Google тоже ответ прислал:
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]
Обратился к провайдеру доменного имени, попросил проверить mx-запись. Специалист сказал:
MX-запись отдается корректно:
dig xxx.xxmx +trace
;; ===============================================================================
;; ASK FROM [8.8.8.8] ABOUT [.]
;; ===============================================================================
; <<>> Net::DNS::Dig 0.12 <<>> -t ns .
;;
;; Got 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: 20 ms
;; 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 answer.
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4672
;; flags: qr rd; 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: 3 ms
;; 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 answer.
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4672
;; flags: qr rd; 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: 37 ms
;; 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 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: 3 ms
;; 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
До сих пор пытаюсь понять что не так с mx