I have the same problem with the IPhone 6. Have the mavic for 4 weeks and everything worked fine in till tonight.  I tested with an iPad air 2 and that works fine.

Has anyone of you tried Litchi App instead?

Yes I'm using the iPhone 6s Plus and it works great no issues.  

Although in cold weather the iPhone 6s Plus  has an issue of shutting down even with full charge. Apple won't help with this issue on all of the devices only some and won't help sort the others!

The only solution is android