AT&T Galaxy S6 screen flashes on and off repeatedly

[AC Question]

Brand new, about a month old and the glitches start!

The screen flashes on and off repeatedly, and so quickly it is VERY hard to push buttons to shut down and then reboot.

Timing has to be perfect. It doesn't stop on it's own, you must reboot.

 

[B. Diddy]

Welcome to Android Central! Try booting into Safe Mode, which temporarily disables all 3rd party apps. https://support.t-mobile.com/docs/DOC-21007

If the problem disappears in Safe Mode, then something you installed is causing the problem. You may have to uninstall apps one by one until the problem disappears. If the problem persists in Safe Mode, then it's more likely to be a hardware or firmware problem. One possible hardware issue would be a faulty Power button.