Hello
I am Abdal and I would be glad to help you with your question.
If you are having trouble exporting a OneNote notebook using the Microsoft solution, there are a few potential causes and solutions to try:
Make sure you have the latest version of OneNote installed.
Try clearing your browser's cache and cookies, and then try exporting the notebook again.
Disable browser extensions or add-ons that may be causing conflicts.
Try exporting the notebook using a different browser.
If the notebook is stored on OneDrive, try downloading the notebook as a .onepkg file instead of exporting it.
Check if the issue is only with a particular notebook or all notebooks, if it's only with a particular notebook then try creating a new notebook and moving the pages from the old notebook.
I hope this information helps.
Regards,
Abdal