Vizio 65" 4K UHD TV & Denon AVR-X1300W Receiver stop sound no reason

I was watching tv a few days ago and all of the sudden the sound cut out from the home theater system but the tv still had perfect picture. I wasn't touching the remote at the time the sound just stopped. Was working perfectly the past 4 months. No idea what to do, I've unplugged everything and reconnected and even made sure the setup was where they were on settings.