Duet 0.6 can't print gcode files

Dear all,
I've Duet 0.6 which is connected to Pronterface via a USB cable.
Heaters are working perfectly, homing is done without issues, accept individual moves nicely, and extrusion goes fine.
The problem is that the printer doesn't start printing any loaded file once you hit the print button. The console shows that the file is loaded and with the expected printing time but nothing moves or happen. I've tried even simple gcode file, for example:

G1 X100 Y100

The above is one line file saved on the computer, loaded to Pronterface, but nothing moves after hitting the start button (tool 0 was selected previously). Also, different firmware was flashed to the board but nothing changed.

Any suggestion please?

SOLVED!
In configuration file put the output compatibility looks like MARLIN (M555 P2) instead of RepRapFirmware (M555 P1) and everything will go fine! Weird?!

This puzzled me as I've not seen M555 for years...

It's the USB connection that threw you.

Quote
dc42
M555 only affects responses sent to the USB port. The default was changed to Marlin compatibility many versions ago. So you don't need it.

Source: [forum.duet3d.com]

So you don't need it if you only use the web interface.
I wonder why? The Duet web interface is awesome!