iOS 16 Widgets not connected

Hello,

it looks like the widgets here on my iPhone 14 Pro can‘t connect to the Nextcloud app. Both widgets show a ‚x‘ instead of free space or usage like it can be seen on several screenshots in the internet.
The Nextcloud app itself is connected and running.

Does somebody have an idea ?

My iPhone is running iOS 16.1, the Nextcloud app is 4.5.4.9 and the server runs on 24.0.5 hosted here in Germany by the webhoster „Hetzner“.

Greetings Tobi