We are using Zoho Desk's Knowledge Base as a Knowledge Management system, and I would like to move subsections to another folder/category/subsection. I have successfully moved most subsections and their articles, but there are 2 folders/subsections that won't move. 

When I click and drag those folders to the new subsection, and when I click the three dots > Move and select which subsection to move it to, I get an error that says "Category couldn't be sorted". 

Why does this happen, and how can I troubleshoot this?