Welcome to the forum!
Have you or anyone else recently moved any part of your system? If so, one common thing that comes up here is that someone moves a speaker or receiver and causes one or more copper strands to bridge across a pair of speaker terminals. This causes a short circuit and will put the receiver into protection mode.
I'd say check your speaker connections carefully and make sure that there aren't any wires bridging across two terminals. You could also disconnect all speakers from the unit and see if this behavior continues.
If bad connections gets ruled out, then you might want to reset the microprocessor using the procedure described on page 43 of the
owner's manual.
