I have created a domain controller and backup domain crotroller these work fine I can join windows clients however whenever I try join a member server it just hangs at the domain join
The member server you’re trying to join, is that a Windows server or a UCS member server?
I had the same problem and worked for ages to try and figure out what was going on. Discovered the solution by a stroke of luck when I was called away from my desk for some time; the domain join did actually complete and works correctly afterwards. I end up leaving it now for over half and hour and when I come back, all sorted.
Not sure why it takes such a crazy amount of time to complete, but I have a working system so haven’t had a chance to look into it any further.