Check the SAP and audio description settings. If either of them is On, turn it Off. If the option is already Off, toggle it On and Off again.
Inspect the HDMI or audio cable to ensure it's plugged in correctly and isn't damaged. If a cable is damaged, replace it. Verify there's no dust or debris in the ports.
Experiment with different options in TV settings. If you have a connected audio device, switch to the TV's internal speakers to see if that fixes the sound. If it does, turn the device off and unplug it for at least 10 seconds. Check the audio settings in the connected device. Make a note of the previous options for any TV or connected device settings you change so you can put everything back the way it was if changes you made don't fix the issue.
If anything fixes your issue, please let us know what you did to fix it.