Good morning!
I've been using hidden album for some time, but I've had a problem with its functionality for a few days. At the beggining I tried to add a photo to the hidden album and there was a message saying that I do not have enough space in Mi Cloud. I've dealt with this but the problem has not disappeared - now I get the message "Can't add to hidden album. Unknown error." and it always appears, regardless of the folder, photo or number of selected files.
Until yesterday, I also had old MIUI, so I updated it to the latest version, but it didn't help.

Does anyone have an idea what I can do in this situation?

Thanks for help in advance and have a nice day!