Yesterday my mavic air was able to take off
and today I am getting  Main Controller Data Error.
My controller can still connect to the drone and take pictures and video but it won't take off.
I refreshed my mavic firmware via assistant and set the controller back to factory defaults and that had no effect.
thanks for any help.

no help__?

Hello there Healimonster. I am sorry to read and to know that you are having issues with your DJI Mavic Air. Would it be possible if the drone experiences any hard landing or a crash before? Have you tried to check if the application would allow you to take off the said drone? You may try to refresh the firmware of your aircraft once again using the DJI Assistant 2, recalibrate the IMU and compass as well as the gimbal to see if there will be changes. The DJI Assistant 2 can be download using your computer and by clicking this link: https://www.dji.com/downloads. If the problem persists, we highly recommend contacting our DJI support team for further evaluation of the said unit. For additional information, the warranty can be applied depending on the outcome of the assessment and if the drone is within the warranty coverage period. If you wish to contact our DJI support you may click the link below. Thank you.

https://www.dji.com/support

DJI Stephen Posted at 5-29 21:14
Hello there Healimonster. I am sorry to read and to know that you are having issues with your DJI Mavic Air. Would it be possible if the drone experiences any hard landing or a crash before? Have you tried to check if the application would allow you to take off the said drone? You may try to refresh the firmware of your aircraft once again using the DJI Assistant 2, recalibrate the IMU and compass as well as the gimbal to see if there will be changes. The DJI Assistant 2 can be download using your computer and by clicking this link: https://www.dji.com/downloads. If the problem persists, we highly recommend contacting our DJI support team for further evaluation of the said unit. For additional information, the warranty can be applied depending on the outcome of the assessment and if the drone is within the warranty coverage period. If you wish to contact our DJI support you may click the link below. Thank you.

https://www.dji.com/support

The previous day I tried to take off inside my house and it did take off. Then I updated the safe-fly database and went to bed. The next day I tried to do the same thing and I got the Main Controller Data error and it would not take off.  When I would go into the settings in the app it listed errors like IMU and other stuff.
I did use the assistant 2 app to refresh the firmware and the same "main controller error" persisted.

Healimonster Posted at 6-3 13:19
The previous day I tried to take off inside my house and it did take off. Then I updated the safe-fly database and went to bed. The next day I tried to do the same thing and I got the Main Controller Data error and it would not take off.  When I would go into the settings in the app it listed errors like IMU and other stuff.
I did use the assistant 2 app to refresh the firmware and the same "main controller error" persisted.

Hi there Healimonster. Thank you for the given update. Since this issue is still persisting even though you have calibrated the IMU and refresh the firmware of the said drone. It would be best to contact our DJI support team at https://www.dji.com/support for us to be able to check the said drone thoroughly and a proper resolution will be provided. Again I am sorry for the trouble this has caused and thank you for your understanding.

DJI Stephen Posted at 6-4 01:38
Hi there Healimonster. Thank you for the given update. Since this issue is still persisting even though you have calibrated the IMU and refresh the firmware of the said drone. It would be best to contact our DJI support team at https://www.dji.com/support for us to be able to check the said drone thoroughly and a proper resolution will be provided. Again I am sorry for the trouble this has caused and thank you for your understanding.

UPDATE:
Thanks Stephen
I contacted DJI and sent the drone in for service. They said the IMU needed to be replaced, fortunately, it was only about $10 more than the flat repair/assessment fee of about $70.

I was very pleased.

Healimonster Posted at 7-23 13:41
UPDATE:
Thanks Stephen
I contacted DJI and sent the drone in for service. They said the IMU needed to be replaced, fortunately, it was only about $10 more than the flat repair/assessment fee of about $70.

Hi there Healimonster. You are very much welcome and thank you for the positive feedback for DJI. If you have any other concerns or inquiries with DJI. Please feel free to post it here at DJI Forum. We are all here to help and support you.