My Sidetone Disappeared Flex 6300

I didn't make any changes to the rig or software. I was working fine in CW. When I left the rig for a while and came back, my sidetone was gone. The rig audio is fine.

I use a pair of Bose power speakers for both rig and computer audio with both audio cables going into the speakers. The rig audio is coming from the speaker port on the back of the righ. Sidetone button is lit, Volume 55, Pitch 580, Breakin is lit. The mode is set to CW.

I can transmit, and if I use CWX I get a sidetone as usual. I have swapped the audio cables coming from the computer and rig and the problem persists. I have rebooted the whole system and it didn't correct anything.

I'm using a Windows 10 PC with SmartSDR 2.7.6.

Any help would be very much appreciated.

73,

Steve, W6SDM