After upgrading to 1.3.1.0 and the latest server (as of 1 December, 2015) I was unable to connect to my media server using the xbox app, various other apps continued to work without issue (Windows 10, windows phone, iPhone, and Roku all fine).
I set the xbox app to log to the server, though held little hope for that since the problem was inability to connect to the server.
Any time it did connect the only thing to appear in the logs was:
Dec 01, 2015 20:40:24:629 [6100] DEBUG - WebSocket: processed 0 frame(s)
repeated over and over again. After various attempts to get it working I finally tracked it down to the secure settings, which after updating to allow fallback to insecure on the same network allowed me to connect once more.
I’m not sure what the previous settings were but the change caused a fair bit of frustration