Testflight app will not lauch if device is connected to cellular data...

As the title says, when I download our app from Testflight it will not lauch if the device is connected to cellular data. The app starts to show a black screen then imediately closes. If the app is active when the device connects to cellular data, the app will imediately close.


If we put the device in Airplane mode or turn off cellular data, then the app will lauch.


Also, if we build the app directly from Xcode and install to device, then the app works fine.*


Is this some kind of security feature? I've searched as best I could to find some documentatiin about it but can not. Perhaps someone out there knows about this?


We are using Unity 2018 3.81f development tool and Xcode 10.1


*The above is not correct. The app fails to load if installed from Xcode as well if cellular is turn on. I am invetigating the error log now.


Update** I believe I may have discovered the cause. It perhaps has something to do with the Facebook sdk for Unity. I found this link here...

https://github.com/facebook/facebook-sdk-for-unity/issues/208