OneNote Stopped syncing. We can't sync this section because the server isn't compatible with this version of OneNote.

Today, I updated OneNote for Mac to v16.24.0 (build 190318)(insider fast). It is kind of working. Existing OneNote files from OneDrive and from Sharepoint on OneDrive can open and sync.  BUT existing OneNote files from Sharepoint 2013 can't open and sync. Same error message. I have many OneNote files from our corporate Sharepoint 2013 server. At least they can be opened via the web browser.

i have been using onenote for 4 years for school now and my notebooks have tons of chapters of notes in them. its not a matter of a message falsing saying a sync didn’t happen when it did. the notebooks literally open up completely empty on the standalone version with an erro saying to sign in to sync notebook when i am already signed in. not to mention i can no longer create new notebooks and i have to fetch existing notebooks from the recent tab instead of file open area. i even uninstalles all of office and cleared all keychains ajd credentials and reinstalles. same issue.

what version are you on?? ive been on 16.24 a few weeks now and check daily and there has been no update past 16.24 somce i last checked today.

Today, I updated my version on mac and it seems to be working.

All, 

Ive tested OneNote for Mac (native app version. MacOS Mojave)and Onenote for windows OneNote (windows 10 professional) Version 1803. Sync does work in real time, However, it is a bug in that no confirmation of sync completion is done. (also, verified it works with Sync on Onenote for Web(via web page access). 

For example, I wrote a test sentence in OneNote for Mac and it properly shows up and syncs all notebooks and changes to my Onenote on my Windows Device. Hope this helps troubling shooting of the issue, 

(it is not sync issue, rather no confirmation or webserver response properly saying sync was done accordingly)

Update: Just prior to posting this. found the issue to resolved.