The error message you are getting is what happens if Scrivener cannot save a file to the location where the project is stored. This typically more often happens with removable devices that got ejected while the project was still open, or if there are permission issues making some files read-only to you. But really all kinds of write errors can cause that error, even a faulty drive cable.
So I can only guess that this cloud service you use is doing something unusual with how it manages files. There may be a setting you can change that makes it sync every locally, if it isn’t doing that already.
But if you can’t find a way to make it work, I second the advice to consider keeping the project stored outside of it, and instead point your automatic backup folder to save to it (in File ▸ Options..., Backup tab). Uploading single .zip files one at a time, whenever the project is closed, is generally much easier to sync to handle that how Scrivener tries to save many files at once from an open project.
I might as well drop a link to this checklist for testing sync services, too.
By the way, I would also like to change the language to Norwegian or English, but can’t find where to do that. And, concerning the Error mentioned above, I have not tried to change a name of the project. THanks for any assistance
You can change the interface language in the General: Language options tab.