Hi

I set up at Windows 2008 server as terminal server and licensing server for 10 Igel thin clients.
I have activated 20 Device CAL's but I only get one issued if I connect from a windows computer.
I kan make the thin client "reset license" on reboot and then I can log in once and the reboot again.
If not I get an error that license was not accepted and on the server I get an event 4005 (something like: The windows logon was terminated unexpected).

I wonder if it might be caused be the licensing server not being installed on a DC? Should I promote my TS to DC (only 2008 server in domain) og could it be another issue?

No, this problem has nothing to do with where the TS Licensing Server is running, it's most likely a problem with your thin clients.
Are they running linux, Windows CE or Windows XPe?
Have you contacted the vendor and checked if there is a firmware update?

If they are behing a different router than your full Windows clients, the problem could also be caused by a black-hole router, which drops packets above a certain size (meaning that it allows the small temporary license to reach the client, but rejects the bigger permananet license). If that's the case, you have to change the MTU size.

How to Troubleshoot Black Hole Router Issues