I was out today getting exercise on a beautiful trail and took my Mini along so I could make some scenic videos after my exercise.  Got the Compass callibration required message and then multiple failures on the calibration.  Was ready to give up when I realized that my gloves had small but powerful magnets imbedded in them.  Took the gloves off and that resulted in successful calibration.  Unfortunately I was so excited that I forgot to start recording video.

Hello and good day JohnK48. Thank you for sharing these information and for sharing your experience with us. Just a reminder in calibrating the compass of the said drone do not calibrate your compass where there is a chance of strong magnetic interference, such as magnetite, parking structures, or steel reinforcements underground. Do not carry ferromagnetic materials with you during calibration, such as keys or cellular phones. Do not calibrate beside large metal objects. Thank you and fly safe always.