Connection problems mobile network

[airstream87]

hi
i can't connect to spotify with my ios app by mobile network. with wlan it works.
the point is:
- i reinstalled the app (twice)
- i updated my phone
and it still says "spotify is offline", and this is not because i manually set it to the offline mode.
other apps work perfectly with mobile network.

can anybody tell me another way to solve that problem?

thank you!
Fabio