protection indicator comes

When the protection indicator comes on the front panel display of DENON or MARANTZ AV receiver or the on/standby red LED flashing continuously what you should do?

The “Protection” LED light flashes on the front panel which means there are some technical issues in the AV receiver, loudspeaker or in the loudspeaker’s cable. If someone is trying to put it on again and again it may cause severe difficulty.
In thermal protection cases, the av receiver will automatically reset after a few minutes of cool down. The protection indicator will go out and regular operation will start.
If the protection light came on due to a speaker wire short, low impedance condition or a defective speaker. The av receiver power should be turn off to reset it. Before turning the power on, all speaker wire connections should be checked for their integrity at the receiver side and at the speaker side.

If the protection light goes on immediately after you turn on the receiver. Disconnect the speaker wires at the receiver side and reset the system. If the receiver’s protection light goes off, then there would still seem to be a problem with one channel’s speaker wires or speakers.
Connecting them one by one and retesting should allow you to find the problem of the speakers or connections.
If after checking All your connections, the protection indicator stays on. Then you may need to initialise the microprocessor. Take your av receiver to an authorised service or repairing centre for diagnostic.
The initialisation of the microprocessor or reset procedure is in your owner’s manual on the latest model av receiver.
Please note:- This will erase all setup. You may need to mark down the settings before resetting your av receiver to aid in the setup process. If you know the authorised service Center of Denon, contact them, they will help you.