How to get the unlock code prompt on AT&T Nighthawk MR1100

I never got it with the T-Mobile SIM either. That’s why I’m assuming it was already unlocked. When I got my T-Mobile SIM, which I just went to a T-Mobile store and bought one for $10, it still didn’t work and was told that I needed a static IP and it would take 1-2 days and I would get an email with instructions on how to proceed. 3 days go by and no email then I saw a post on their Facebook page from someone in a similar situation and on a whim he factory reset his Nighthawk without a SIM in it and then put the T-Mobile SIM in and rebooted it and it was working. I followed the same thing and mine was working as well. So the static IPs must have been assigned but they just never sent out an email letting us know. Still haven’t received an email and it’s been about 10 days. Just got lucky stumbling across that post on the OTR Facebook page.