Lost access to section on OneNote

[tsabr share]

Hi, I've got issue about OneNote

In my Notebooks under title : Notebook Tu****k there are 8 section but i lost my access to 5 of them i.e

1. Arcieve

2. Important

3. Favorite

4. Correspondent

5. Web Address

In all those Section, as shown by the tittles, there are so many Important Data and Secret Notes...

In this case i wanna ask to the community why that case can happen... I mean is that happen because of hackers or tecnically error on my OneNote?

How i can fix the problem?

Would somebody can give some advice or tecnical suggest?

Thank You

[#2]

I would recommend asking this question in the OneNote community space. where it will be seen by more people who have expertise with that application.
This Space is typically used for general purpose questions about the overall community.