Why doesn't DNS mail.ru resolve my server?

Question

Domain Name System

DNS mail.ru does not resolve my mail server, and write back (PTR)
Letters go to mail.ru from me, but letters do not reach me (retry time exceeded)
However, if I make a "reply" to a letter that came from my domain, it comes (takes the correct address from the body of the letter
) Everything is fine with other mail services (gmail, yandex). Mail.ru support says that the problem is not on their side.

Answer 1

And where did you get the idea that there is an externally accessible DNS server at 94.100.178.70?

# dig NS mail.ru
;; ANSWER SECTION:
mail.ru.                370     IN      NS      ns1.mail.ru.
mail.ru.                370     IN      NS      ns2.mail.ru.
mail.ru.                370     IN      NS      ns3.mail.ru.
;; ADDITIONAL SECTION:
ns1.mail.ru.            596     IN      A       217.69.139.112
ns2.mail.ru.            596     IN      A       94.100.180.138
ns3.mail.ru.            54      IN      A       185.30.176.202

Answer 2

Well, open your face, show the domain. At least see what dns gives)
otherwise - I have a problem with something, but with what - I won’t show you)