Intermittent issue with WSJT-x keying up SmartSDR … but no RF power going out.

KB1FX

I have a 6600M and use SmartSDR both v3.2.39 on a Windows 7 computer.
I use WSJT-x v2.5.4 with SmartSDR on the computer for FT8.
No amplifier, external tuner or meters.

WSJTx works as intended 99% of the time.

I have an intermittent issue with WSJT-x keying up SmartSDR … but no RF power going out.

The radio’s PTT & MOX buttons turn red & I can hear the TX relay in the radio click.
The MOX button on SmartSDR turns a muted blue.

The MOX button on the SmartSDR TX panel is a muted blue color and clicking the MOX button does nothing.
I need to click Halt TX button in WSJT to un-key the radio.

If I click the halt TX button then click the enable TX button on WSJT
it will start transmitting.
This also happens in clicking enable tx button 1st attempt and in auto sequence.

There are no pop-up error balloons when this happens.

This is intermittent and tried several operating conditions: Including,
Using Smart control mode on the 6600M with only 1 slice open in SmartSDR.
Different antenna’s & feed line.

I have not seen this issue if using the slice on the 6600M, but
I have only used this method a few times.
I prefer to use the slice on the 6600M for SSB & SmartSDR for digital

The GAP vertical antenna has a perfect SWR below 1.5:1 on 40m-10m.
The issue occurs with auto-tuner turned on or in bypass.

I generally run at 50 watts, but has also occurred running 1 watt into a dummy load.
No one thing seems to cause the issue

I guessing there is a “missed” setting in the radio, SmartSDR or WSJT-x

73's
Mike ~ KB1FX