category and image not saving

Hello,

I’ve come across an issue where I created 9 categories. Each category has 3 or more images.

Now I can not create a 10th category. If I create it and save the changes it says “Changes saved..!” but when the page reloads I only see 9 categories intead of 10. Everything after that is not saved even though it tells me it was saved. I can also not add anymore images to my last category. Why is that?

I am not getting any warnings or indications why this bug is happening.

What can I do to add more categories and have everything saved?
Could you please help me with this?

Thank you so much in advance!