I experienced what may be the same, or similar, issue.
Same error and problem, happening in desktop OneNote (macOS).
OneNote can't connect to the server. Sync will resume once we connect. You don't need to take any action. (Error code: 0xE000146E 72at2 10017 | b78bccb4-a466-ba48-9970-338873d606ba 202311062323)
One notebook was doing this, whilst the other one was not. Both notebooks were in in exactly the same folder in the same location on a Microsfot business account. There is obviously no actual issue with the connection to the server, since one notebook is connecting fine.
The only solution I found worked was to log out of the account on Onenote (desktop app). The changes that couldn’t be synced were then put aside, as Onenote does in such situations). I then logged in again, and syncing was no longer an issue.
I share this in case someone else finds this discussion thread, and perhaps this is an easy solution for them also.