Is the data static? IOW, is the accumulated miles reported via the app staying exactly the same over days? If so, to me at least, it sounds like the Telemetrics module is in a fault loop. See if you can get BMW to reset your account, and if that doesn't help, try removing and replacing fuse F115...that will force the telemetrics unit to do a reboot. After a couple of weeks of back and forth with BMW, that is what it took to resolve my communications issue. Note, the dealer took the rear seat off and removed the plug from the module then reinstalled it. I afterwards got him to look up which fuse powers that module, and that's where I got the F115. I have only had this happen once, and rebooting the telemetrics unit 'fixed' the problem. It was very evident...it would not work, he unplugged it and reinstalled things, and my phone app then worked.
Personally, I think some of it is server issues, but I also believe, at least in the USA software version (may be the same on this elsewhere as well), that there's a bug, and some unusual set of circumstances will cause it to lock up and not be able to recover except on a reboot.
Proceed at your own risk, though.