Unable to add my own playlists to a folder

[fantasticat]

I saw that many other people had the issue that I has, wher they were unable to add any playlists to a playlist folder. However, they each found solutions by creating a new playlist in the folder, then adding their playlists, then simply deleting the dummy playlist, or by creating a folder inside the folder.

Although, neither of these worked for me. I am able to drag and drop any playlists created by other users, but any playlist I have created cannot be added to the folder. I have tried dragging and dropping the playlist from my user interface and from the search results.

I see the small '+' icon, however there is never a playlist added to the folder. I use the Windows 10 desktop app.

Please recommend a solution to this problem as I have many playlists to organise.

Thank you.