Can't license server 2012

Hi, I built a server in a KMS license environment and then moved it to a DMZ, so it needs to be activated by phone.

I've got a MAK code, which has been used all over the estate, and i've used:

slmgr -upk (to remove the kms links)
slmgr -ipk <mak> (to add the new key)

and it says it's loaded successfully but when I run slui /4 it says Access Denied, contact your administrator. (Hi!) and when i run slui it asks me for a key.  If I use the same key, as before it says This key didn't work, please check it and try again or try a different key.

I get this in event viewer (googling now) - License Activation (slui.exe) failed with the following error code:
hr=0xC004F074


Any tips?