I had this issue yesterday. I got my Atrix on Monday & when in my house, I had AT&T Microcell in the top bar. Then yesterday, I started noticing that I had no network covereage (red Circle in place of H+ & bars). I rebooted the microcell - same issue. I logged onto my AT&T account & went to my microcell page & there in big red letters was a message to the effect that the MCell only supports 3G devices & that my phone was not a 3G device. So I contacted AT&T and the Lady I spoke to was extremely helpful. We opend a trouble ticket & low & behold within 10 minutes I had AT&T Microcell showing up on my atrix. What changed at the back end was they added the microcell provsioning which was absent. So that might be your issue here too. Worth a 611 call at least. Hope this helps.