Hi @it33,
I'm having the same issue since I upgraded to Mattermost 2.2.0.
With v2.1.0, it worked fine but now I have no more notifications on my device.
iOS app is up to date, I logged with the right account (I did try to login / logout) and I'm receiving the mail notification.
However, nothing on my iOS device now.
As @andreugrimalt, I have the "Sending push notification [...]" debug message in the log.
Thanks