Hi Joern, sorry for the delay. I have been very busy. Could you send a GET request to <deconzip>/api/config, please? You do not need an API key for that. Please share the response.
Could you share your crash identifier? First please make sure that the app crashes. After that, in the screenshot you sent, tap the advanced button at the bottom and you can connect a demo bridge. Then you can get the crash identifier using these steps: Crash identifier. To remove the demo bridge afterwards, just close the app from your recent apps screen.