No files visible on Tablet and Smartphone APP

Installed latest stable 10.2 and the APP on my Samsung p600 Table and on my Honor 9 Smartphone.
If starting Nextcloud APP - loading - appears and then - no files available- Keine Dateien vorhanden in german.
What’s my mistake?

@Ren_Dark which version of the mobile app are you running, btw. latest stable of the server is 12.0.2

App 1.4.3
I’m shure that i’m installed the latest version, but how2find the versioninformation with web frontend?

also i can not upload a file or create a folder

Via Webdav from Smartphone no problem

If you go to the admin section on the web interface and scroll down a little you should see the server version.
As for the other issues, it is best to open an issue on Github so there can be a discussion with all the developers:

They might need a test account though to debug this issue (folder/file creation).