DAX TX Audio not reaching radio.

Flex 6600, SmartSDR 3.4.21, Fully patched Windows 10 Pro

When using a digital program (WSJT-X, but I don't think it matters), my transmit audio is not making it to the transmitter.

• I'm in DIGU, and the DAX button is on (Blue).
• I see good levels (about 2/3 scale) of audio on DAX TX, and it says it is streaming.
• If I switch DAX on and off in the SmartSDR window, the TX button in DAX switches between blue and yellow as expected.
• However, no audio appears in the Level meter bar and of course all the later stages (Compression, RF Pwr, and SWR) show no indication.
• If I press the Tune button the RF Pwr and SWR meters behave properly.
• If I switch to SSB, the radio behaves normally.

I know it is a setting somewhere on my computer, because things work correctly on my wife's computer. I just am out of ideas of what it might be.

Thanks for any pointers you may be able to provide.