Kindle PW 11 no longer recognized in Calibre 7.3

Hi,
I've got a Kindle Paperwhite Gen 11 and am using latest Calibre 7.3 on PC
When Kindle is connected to PC and Calibre open, Kindle no longer shows up in left hand column in Calibre display (usually says "on device" or something similar)
This has been working for years, through various Kindles and Calibre updates.
Any suggestions on what to try, or ideas on what has changed?
Thanks