Since the update 0.9.20 till now (0.9.23) I have the same problems.
Using Win10 64 bit pro, Marlin Laser (DexArm from Rotrics).
With 0.9.19 all worked fine.
Now Laser is ready mesaage but “Waiting for connection”.
115.200 baud is enabled. Nothing changed in my preferences.
Still not working.
Restarted software, laser, pc, reconnectaion many time. no change.
getting no connection.
Degrade to 0.9.19 all works instantly fine…
I asked at Rotrics to support you with a free Dexarm to develop your software for “our” laser with Marlin and circular engraving limitations.
Hopefully they react positively.
Kind regards