Unable to download files from iCloud on my iPhone

For a few days now I've been having trouble downloading files from iCloud on Files app. It gives me an error "The operation couldn't be completed. (NSFileProvider-ErrorDomain error -2005.)" and I can't do anything. In the first few days when it started to crash like this, it would fix itself after a few hours. However, for two days now I can't download any files. Does anyone have any idea what's happening?

[Re-Titled by Moderator]