In the device manager, when looking at cameras tab (which is default tab upon logging in) you get a prompt stating.. 

"System Unavailable.... Your GS2 processor is busy applying updates. This process may take several minutes. Once updates are complete, you'll be returned to the admin utility." 

This can loop indefinitely if a camera is disconnected or having connection issues.

Workaround: To gain access to the device manager, click out of the 'Cameras' tab and the prompt should stop appearing (you may have to try this several times).

Version(s) effected: All 19.3 builds

Fix implemented: 19.10