I can't add .vtt subtitle to my video on Onedrive.

Hello!

I need some help about this issue, because I don't know what's going on. I'm the owner of my Onedrive, and all the files, I have all the permissions, but every time I try to add a .vtt file I get this error. The subtitle is fine, I tested it already, so I don't know what's the problem here.