My Phone Did the Same Thing ..... So Here's What I Did 1.) Took My Phone Out The Case ..... (If Its Hot wait for it to cool off) 2.) If It Is Hot Cool Down for 15 Min (I Put Mines In The Freezer For 3 Mins) 3.) Hold The Power Button For A While 4.) Turns On with App Optimizing if this don't work hold the power and volume button.