I have multiple clients synching to OneDrive. My system has been running flawlessly for quite some time.
In the Windows client, I can not drag a note object onto the tag in the left-hand navigation. This has worked in the past and still works on my Linux Joplin ( 3.0.15 ).
I figured out how to turn on debug, and Joplin is complaining about a NULL value for the INSERT into table 'note_tags'. I have tried disabling all plugins and I have tried Safe Mode -- no joy with either.