IPadOS seafile folder in File App is read only

I have installed SeafilePro 2.9.3 on IPadOS 13.2
Seafile Server is Version 7.0.4.

I tried to edit some .md files with IA Writer and always get the error that I don’t have the right permissions on the folder (the seafile folder).
The File App shows the Seafile folder as read only. I can access all files but i can’t edit any file.

In the WebUI and with the Desktop Client everything works fine.

How can I edit Files on IPadOS?