It's wonderful news that the issue has been resolved and thank you so much for sharing it!
Your discovery is especially valuable because this issue has been quite tricky to pin down. I’ve searched through Microsoft’s official documentation, technical communities, and support channels, and there hasn’t been a clear answer or workaround published for this specific scenario. That makes your contribution all the more important.
You’re the first to share a working solution for this issue, and I believe many educators facing similar challenges will benefit from what you’ve found. Thank you for taking the time to follow up and share it with the community.
Therefore, I would make a brief summary of this post so that other forum members could easily find useful information here:
Issue Description
When attaching a OneNote page to a Teams assignment, the interface did not recognize sections inside Section Groups or manually distributed sections, even though they existed in each student’s notebook. The system reported “no sections available.”
Assessment
This behavior appears to be a limitation in how Teams Assignments currently detect available sections, especially when using OneNote for Windows 11.
Solution
Using the Manage Notebook feature in Class Notebook (via Teams or browser), the user distributed a new section. After doing this, the section inside the section group became visible in the assignment interface allowing the OneNote page to be attached successfully.
A happy accident, but a helpful workaround!
Thanks again for your contribution. If you found this helpful, feel free to mark it as an answer or upvote it’ll help others find the solution more easily.
Warm regards,