This problem is driving me insane (I'm on Verizon btw). It's not my router either, it does this on every network I connect to. Lately it's becoming more and more frequent, in the last 24 hours it's probably dropped my connection 6 times. There's no sure fire way to get it working again either. I'll restart the router- nothing. I'll turn on and off the wifi and mobile data- nothing. I'll forget the access point- nothing. I'll restart the phone- nothing. Then it will just randomly connect back to the network several minutes later. This is completely unacceptable considering the cost of the phone, the whole reason phones are like this today is for their internet abilities. This is also my second HTC One M8, the first one was returned due to a stuck pixel. The first one had the same network problems, the new one I got wouldn't connect to the network straight out of the box (I thought it was broken) and seems to have worse wifi problems than my original one. It's unbelievably frustrating and HTC needs to send out a patch for this ASAP.