Instant shutdown

I logged in today for the first time and after accepting credentials, the app shut down. I tried to recreate the problem, but could not get it to not-work :) I had almost no other apps running in the background so it was definitely not a RAM issue.

iPhone 5s

iOS 9.0.2 JB

Edit: Apparently it is related to internet connection problems. A minute ago my phone connected to a McDonald's hotspot. It does not allow direct connection to the Web (you have to accept the terms first). I didn't see that and launched the app, which was running in background. It shut down instantly. I switched to LTE and it worked fine. I hope the description is good enough.