No Jog movmement

[rich44]

Using Mach 3 with a UC100.

When setting up my mill, I need to use Step mode Jogging. This works some of the time but sometimes it just stops moving the machine. Once this happens all Jog controls stop working. Step and Continuous.

I can only start moving the machine again if I hit RESET.

I initally thought this was only happening when the spindle was running, but I think it happens while its stopped too.

What can I check?

I saw someone else post a similar issue but didn't see any fix for it?