When trying to connect by NoMachine from a chromebook running Chrome OS v. 77 or later, the client hangs on the spinning wheel at stage 'Connecting to ...'. After some time the application becomes completely unresponsive and eventually closes itself.

This problem is not reproducible on earlier versions of Chrome OS (e.g. v. 76). It looks to be triggered by some changes introduced by Chrome OS to the Android Runtime.

Based on some reports and lab tests, users cannot connect by NoMachine v. 6.1.9 on the following Chromebook models and Chrome versions:
Acer CB3-431 - Chrome OS 80 Beta
Dell 3400 -  Chrome OS 78 and 79
Samsung Chromebook 4 - Chrome OS 79
Samsung Chromebook XE510C24 - Chrome OS 79

Connections by NoMachine work instead on the following models and Chrome versions:
Lenovo S330 -  Chrome OS  77, 78 and 79
Lenovo C330 - Chrome OS  78
Acer CB3-431 - Chrome OS  76, 77, 78 and 79