Phone just hangs up?

I dunno if it's AT&T or my phone. I sometimes have to redial a number 3 or 4 times before it'll go through. It often just hangs up before trying to dial. Anyone else experiencing this? It's been doing it for months really but lately it seems to be a dozen times a day. In different markets to (I travel from Pittsburgh to Columbus or Cleveland nearly every day).

Sent from my SAMSUNG-SM-N910A using XDA Free mobile app