HDMI starts at the cable box then connects to the stereo receiver, then connects to the tv. Through HDMI 1. Separate HDMI cable from Bluray connects to TV through HDMI 2. I currently lost stereo and tv sound.
If the receiver has HDMI it is a surround sound or AV receiver. Check the input set up menu to see if the HDMI inputs are still selected for audio on both inputs. You don't mention picture so I assume that is working as usual.
Sometimes a receiver loses settings (similar to drivers not loading sometimes but a reboot won't help on a receiver).