ok if it is greyed out, then it is running.
Try this:
Leave SUT to where its start is greyed out, plug the usb into the computer but NOT the mydmx 3 dongle, hit the register interface button, and then when it say plug in the hardware, plug it in then and it should pick it up.
I made a video on this: https://youtu.be/_odKzbp7cKs
Tell them to watch it.