Oso asked if you're actually connected to the AC with the app? Please confirm. If you're not, it will show blank readings as the AC isn't communicating with the app.
OK, well it didn't attach unfortunately. So, how long have you had the AC? Did you buy it new? Has it flown ok in the past and what, if nothing, has changed since your last good flight? Have you had a crash?
Until.....? What's the reason you're trying to calibrate the compass? Have you tried calibrating the IMU? And what version of the app are you using?
Hmmmmm. So you've done one thing since the fall - you've updated the app? Did you connect to the AC at that time? Do you get any warnings on the app when you connect? Can you start the motors? I guess you could try deleting and reinstalling the app?
If it's less than a year, perhaps a call to DJI and see if they'll look at it under warranty?
