What do i do when the screen flashes "protect"?

The Amplifier is overheating which is causing the unit to go into "protect" mode to prevent any further damage.

If you let the unit cool down it should start up again. When it does you need to check that all the speakers are producing sound correctly i.e. no crackles, hisses or buzzing. If any do not sound OK then disconnect them and see if you still get the fault. If all speakers sound OK then the fault is internal on the Amplifier circuit and it depends on your Technical ability if you wish to investigate this further.

Please note that repeated overheating and cooling of the Amplifier will eventually cause a total failure.