Pro tip for anyone trying to check if a DNS record is working: do an NS lookup in cmd (Windows) in interactive mode. Set the server to the IP of a root DNS zone network (you can find these on Google) then enter that. Now do an nslookup for the domain you want.
Actually no. The first step would be to go directly and query the nameservers set in the whois record (not the registrars which could be wrong but the registry).
For xbox.com that is:
Name Server: NS1.MSFT.NET
Name Server: NS2.MSFT.NET
Name Server: NS3.MSFT.NET
Name Server: NS4.MSFT.NET
Name Server: NS5.MSFT.NET