I have started getting, "Battery not installed proerly.  Unable to take off. Chack and reinstall battery," on my Air when connecting to it.  Everything looks normal, battery information and voltages are displayed but it will not take off.

Here are screen shots of the problem:

Turns out this is a common problem. Solution here: https://forum.dji.com/forum.php?mod=viewthread&tid=170593

BayouWilly Posted at 4-14 17:44
Turns out this is a common problem. Solution here: https://forum.dji.com/forum.php?mod=viewthread&tid=170593

Hi, BayouWilly. Thank you for reaching out. Glad to read that you were able to find a solution. These are our recommended Troubleshooting Steps if ever you experience it again in the future:
1. Check whether the battery buckle is mounted properly.
2. Use a dry tissue to wipe the metal contact pins on the battery and the contact pins in the battery compartment.
3. If the issue persists after several attempts of mounting the battery according to proper guidelines, please send the product back for diagnosis.

To ensure that the battery can be mounted properly, DJI has built-in a detector inside the battery compartment. If the prompt pops up during use, please check whether the battery and the buckle are mounted properly. If the issue persists after several attempts of mounting the battery according to proper guidelines, please send the product back for repair.

Thanks DJI, I love your products so much))