Can't create a new classroom notebook

Split from this thread.

I'm a technology specialist at an elementary school, and one of my teachers has this problem.  When trying to create a new Class Notebook, she gets this error message... 

"Something went wrong. Try creating the notebook again.  Reference number: 5c34****-670b-4e96-9313-****39f09ab0 ... 500 (error) | eus-000.classnotebookapi.onenote.com"

The message contains a "Send this error to Microsoft", which sends an email to edunotebookerror@microsoft.com.  Unfortunately after sending an email to that address, I get an error-message email back from Microsoft saying I can't send an email to that address because I'm not a member of that group.  The message shows that the email was forwarded to another microsoft email account before this error email was generated.

So that's why I'm on this forum--the contact info in the error message doesn't work, which vexes me a tad, but I'll move on.

Here's what I've done to troubleshoot:

• I've restarted the Windows 10 laptop computer multiple times.
• I've cleared the browser cache then restarted the browser.
• I'm using Chrome, but the problem persists in Edge and IE.
• I'm unsuccessful both starting from OneNote 2016 (using the Class Notebook tab) and starting from within our LMS, which is called itsLearning.
• I AM able to create a Class Notebook from another teacher's account.  The process looks identical from both teachers' accounts until the final click, after it asks you to inspect whether the notebook looks properly configured.  After clicking NEXT or whatever from that screen, I get the error message described above.

The problem has persisted over several weeks now.

By the way, I've had a bit of frustration trying to use this forum, too.  Clicking the "Insert Image" button at the top of this text editor field using either Chrome or Edge results in a frozen window--all entered text lost.