Stock Radio not playing sound.

I have a stock stereo, non-JBL, in my 2012 crewmax. Last week the sound on the radio stopped working. I have checked the fuses on the amp, and the fuses for the radio. The radio powers on, shows the channels and information for the radio station and XM stations, but no sound out of any of the speakers. I pulled the radio out of the dash and checked the connections and they were all snug and not loose. Also checked the connections on the amp and those were all snug and not loose. Is there anything else I should check out to find the issue?