Cura Suddenly Dropped Printer and won't Reconnect

[plebe 3]

UM3+ never had network issues. Printing fine for weeks. Always use Cura to Print Over Network option. Finished a print job and suddenly the next one can't connect to the printer. No updates that I'm aware of with the exception of WinOS updates. 

1. Printer shows in monitor tab.

2. Network refresh shows printer fine. Selecting it shows option to "connect"

3. Clicking connect brings printer up in Monitor window. 3 seconds later, the printer disappears again and I can only Print to File from Cura.

4. Tried saving to a USB stick and the printer begins the job but no filament is extruded. 

 

Power cycled printer many times, restarted computer and Cura many times. Even restarted my network switch and Wifi router (which is my DHCP). nothing seems to work with same behavior.

Something obviously went haywire. Ideas where to start?

 

[plebe 3]

Annnnnnd, as mysteriously as it appeared, the problem is now gone. Go figure. I'll leave this post here for suggestions on why this might happen.