Why does my phone turn off and on by itself?

"You might have a conflict with a 3rd party applications.

Try stopping any newly installed applications that might be running on the device. (With two fingers, swipe down from the status bar to open Quick Settings panel, and then tap Settings > Apps > Swipe to Running page > tap on the application you wish to stop > Stop)

http://www.htc.com/us/support/htc-one-m9..."

"I am Vedavithpandi i am also has a HTC with same issue i find out a solution now my htc is good

Belive or not

Just put my phone in vibration mode after some hours i make my phone full charged after 24hours my mobile problem solved just try

email: vedavithpandi@gmail.com"