Im running a Rumba board, I cannot seem to connect to Simplify3d machine control to the board. I have no issues connecting via usb from the Arduino IDE and the board shows up properly on Com3 on windows 10 64.

When i try to connect using simplify3d machine control on com3 it doesnt connect. I have tried all baud rates, tried other cables. but it flashes firmware fine. so that should make any difference.
also doesnt work with Printrun interface

Running marlin 1.1 RC4