i have a M7 HTC One from Tmobile with 4.3 with Sense 5.5.
If my HTC One is longer than ca. 20mins in Standby it has no Internet Connections over Wifi. I changed the Stand By Setting to "Always" but it didn't helped to me.
Energy Save Mode isn't activated. I Also tryied to change the Name in "Wifi Direct" - didn't helped! Done a Factory Reset and the same with my AVM FritzBox Router....
PLS Guys help me!