IOS 10 and Xcode 8 Today Extension does not work on device

Question

I have an application with the Today extension and now I have upgraded from Xcode 8 beta 6 to Xcode 8 GM.

In Simulator, everything works fine, but Today Extension does not work on the device.

The extension stops working when I add a subview, but there is no crash or something like this line in the output window:

Program terminated with exit code: 0

That's all: (

Any idea what I can do or how I can debug it?

Thanks Stefan