No Sound in Right Front Speaker- Denon AVR-1508

Question

Just bought new Denon AVR-1508. No sound coming out of right front speaker. I have checked all speaker wires and the speakers themselves. I also swapped the speaker wires on the back receiver ( so that right was outputing to left speaker) and same problem, so have determined it is something with the receiver's audio output to the right front.

Thanks in advance for help!