How to set up DNS records for a domain?

Question

Domain Name System

Mailgun wants the domain to be like this:

The domain is like this:

Everything seems to be correct, but mailgun says that there is no value and third-party services also say that the Answer Section (basic response data) is empty.

Answer 1

Try to swap

Answer 2

Put A-record?

Answer 3

The first one that came across: https://yandex.ru/support/pdd/set-mail/cname.html read from the place "Dot at the end of the name ..." well, or everything to your liking ...
ps if real domain names are indicated - already for a long time it was possible to make a diagnosis, for example, with the help of nslookup