Why doesn't Skype/YouTube work in a domain?

Question

Domain Name System

Attention, very strange story!
In a corporate network the server with the Active Directory + DNS + DHTsP is lifted. There are two computers through which it is impossible to send/receive messages on Skype ("sending" spins and that's it), and open YouTube (YouTube says that there is no Internet connection).
The most interesting and mind-blowing: if you assign a static IP address to a computer, then everything works until AD synchronizes information about the name of the PC and its address (as long as it "remembers" the old address of this PC). Changed the name of the PC and its IP, after deleting information about them on the domain controller. Everything worked until the AD "learned" about the presence of such a PC with such an IP address.

Answer 1

DNSami for these PCs is the domain controller?