Owntracks with Android 7 over Websockets


is there anyone who got Owntracks working with Android 7?

I would love to see an tutorial for Android 7, since there might be a bug in the software.
My MQTT Broker is HiveMQ which provides Websockets on Port 8000
Furthermore Nginx provides the Websockets connection on port 443.

But i can’t connect to the Broker anymore. This worked on Android 5/6.