I've got an 3018 chinese cnc.
I connected it to my windows 10 PC with arduino ide / Grblctrl and I can connect to the device via USB /serial (USB-CH340 controller).

I get the message "Grbl 1.1f ['$' for help]" when I start IDE / Grblctrl

After that nothing: I can't give any command to Grbl. $, $$, ? they don't produce any output.

Any idea how to fix this?

Thanks in advance.