Below is a list of suggested steps to help troubleshoot the issue of Microsoft Classroom not syncing with OneNote assignments:

1. Ensure that the OneNote Class Notebook is assigned to your student in Classroom
2. Check the assignment description in Classroom to see if it includes instructions for how to open/accept the assignment in OneNote
3. Verify that your student is logged in to OneNote
4. Ensure that the student’s login preferences have been set in the account to use the same Microsoft account as is used for Classroom
5. Verify that the student’s Office and OneNote are installed and up to date
6. Ensure that the reported system or application settings are correct for the OneNote desktop app