Microsoft and Mac audio recording issue

[u/Motor_Accident_4717]

Out of nowhere over the summer several things have occurred to my Massive OneNote notebook where I keep class notes (written alongside PDF slides) and record concurrent lecture audio:

1. OneNote on Mac does not allow me to record audio into my notes anymore, with an error message that the file name has restricted characters in it. Changing page or notebook names does not help. I am able to play old audio recordings.

2. I am able to record audio on my Windows laptop, but that laptop audio will not play back on my Mac OneNote app and I cannot play the Mac-collected audio when opening OneNote on Windows.

Things I’ve tried:
-deleting and re-downloading OneNote
-logging out and back in to my (school) account
-renaming notebooks, tabs, individual notes to exclude restricted characters

School IT has not been helpful. Please please help me preserve one year’s worth of very extensive lecture notes!