Do corporate websites not open in the new domain?

Question

Domain Name System

Good afternoon,
the situation is as follows:

We created a domain: test.ru
entered computers into it,
but now our corporate sites do not open, which have the same name: test.ru, mail.test.ru (located on different external servers)
By pinging these domains, you can see that the domain controller responds. I'm assuming it's a DNS issue. But I don't know what exactly to set. Any thoughts?

Answer 1

It is reasonable to create an AD domain in this case on a separate subdomain, for example office.test.ru

Answer 2

The issue was resolved:
Added A-records to each site that does not open.