There are a few reasons it may want to land. Low battery and loss of control signal are two. It's hard to say without more info as Alok noted. If you are ascending straight up (which is not a good idea) then you may be losing control signal and RTH is kicking in. Just one example.Whenever I fly my P3 standard drone up high and then descend, it says "it will land automatically" and I have to cancel every time. How can I get rid of having to do that every time?