CNC disconnect issues

I have an intermittent problem. I can connect OK and have used my CNC machine many times without any issues, but recently I have been getting port disconnect issues. Not sure what is going on, but the machine can be running fine and suddenly connection is lost and the job is ruined.

I have tried changing the nano board (CH340 clone) and also tried changing the USB cable too. The cables have ferrite beads attached to stop interference. I have checked that all connections are good, and still cannot find out why this is happening.

Any help or suggestions would be appreciated.

The NANO is the absolute minimum board for CNC.

Of the ones I have here there have been at least two occasions I have had to re-load the GRBL firmware. One of those occasions was random disconnects on a windows 10 based computer with UGS.

You neglected a few details. OS, Software being used for CNC control etc..

BTW your URL link is pooched.

And moving this to control section.