I think it had something to do with ATT, today is working like nothing happened.
Strange, today mine was not working again for like 2 hours. I finally walked outside, connected, came back to my desk and plugged in USB. Working fine now, but you maybe correct. Ex-Wife works for AT&T (like 12 years) and claims they go down OFTEN!! Not for long, it could be seconds, but that second is all it takes to drop a call.