So recently I tried calibrating the Mavic pro and air  in all ways and in wide open fields and it still says electro magnetic interferance. I tried it multiple times
Reinstalled the app. Firmware all updated and also making sure I do not have watches, ring, any metals or electro magnetic things. The error is still showing up.
I found out the solution.

IMU calibration worked fine only the compass was having an error electro magnetic interferance.

The problem was the Iphone X <-- This phone really is having lots of issues for drones
I used another iphone  which is 6 and iphone 7
it worked fine!

COmpass calibration fixed.

Thanks for the info... I was having exactly the same issue!!

Kune Posted at 2018-2-6 11:30
Thanks for the info... I was having exactly the same issue!!

While I have not experienced this, I have seen it listed on other Mavic forums.  Apparently the iPhone X can cause magnetic interference issues.  As a habit I never calibrate the Mavic near the phone/ RC.

well thats really interesting, thanks for sharing - i was recently watching the a you tube clip of a guy measuring/ comparing the differance in electromagnetic out put/interferance of devises in airplane mode and out of airplane mode. in airplane mode the smallest green blip - out of airplane mode and shoots to max red zone immediately

Why were you calibrating did the app actually tell you to calibrate? If not seems like you cause yourself some headache

Also you are going to get interference and some spots just move to a different place also to note you will always get electromagnetic interference in the house this does not mean you have to calibrate as long as the values are green when you move to your new destination you are fine

$gambino$ Posted at 2018-2-6 19:56
Why were you calibrating did the app actually tell you to calibrate? If not seems like you cause yourself some headache

Yes the app noted to calibrate compass. Also DJI advised this as well if flying on a new location always calibrate compass for safety.   I was on the most open field with no trees or  house around yet i get the electromagnetic interference issue.  The problem was the phone itself iphone X cannot calibrate compass it will prompt electro magnetic error even there is no electromagnetic around. All other phones worked fine except for iphone x.  

Dear. Sorry for the inconvenience caused to you.
Actually, the model of the mobile device won't influence the calibration of the compass. We do recommend to be away from signal interference when users are calibrating the compass.
BTW, glad to hear you have fixed the issue. If you have any further questions, please feel free to contact us.
Thanks for your support.