FT8 TX not working

Before anyone says anything, I've done a pretty thorough search here and watched a few Youtube videos by Flex guys and though others have had a similar issue, the fixes discussed have not worked for me. It is very frustrating and I would like to get FT8 working before Saturday (NM QSO Party).

So here's what I have: Flex6300 with latest firmware upgrade, DAX 3.1.12.51 , WJTSx 2.3.1 running on Windows 7. The RX Stream looks OK (Slice A and DAX 1 same on the radio as on DAX, streaming indicated (but no FT8 audio and a red waterfall with 15 second breaks.) Audio is set to DAX Audio TX and DAX Audio RX 1. DAX is selected on the 6300 along with DIGU for mode. But the DAX Control Panel TX 'button' is red with message "Unable to open the DAX sound device, ...." and Driver Error. Under FT8 Settings, Radio, the CAT button goes green and the TX Button goes red, indicating what I take to be 'all ok.' But obviously not.

For what it is worth, here is the radio info:
Serial: 0815-4175-6300-1883, Max Licensed Version: v3, Radio ID: 00-1C-2D-02-07-32, Radio IP: 192.168.137.88, Radio Internet: Available, Radio Firmware: v3.1.12.51

Additional setting provided upon request!

Russ
K5FJR