R0B0_Ape

Hey Bart, Not sure if you ever found a solution. It was happening to random imaged computers for me as well. I was able to trace it down to bad DNS/DHCP records. I deleted the records (which were assigned to other computers, btw), performed an ipconfig /release-/renew and I was able to get the pop up for authenticaion. You can also try changing the computernames. Unfortunately that was not an option we wanted to pursue. Good luck.