Iphone -Cannot upload - Error: Cannot create subfolders

Pretty much as described. I’m using the docker image with mariadb. And put it behind a NGINX proxy.

I encountered “Error: Cannot create subfolders” (something like that in my language) when trying to upload photo. Background auto upload doesn’t work neither.

At first I thought it is a SMB issue, but it is not.

Is it just the ios-client? E.g. can you create a subfolder via web-interface.