Why the APM 2.8 turn to RTL from Auto itself...It was not completing own mission

hi everybody ! I have very problems with APM. Also When I send the plane auto mission fly it after 200 meters change to RTL from the Auto itself. Also lost the video receiving clean in spide of I use Patch antenne in very short distance.
why the APM turn itself RTL. Also I have radio ling 433 hz long distance impossible lost control in so like very shortly. Before that when I was using Cyclope it was not same… I could get min.10 km from very clean video and PA code… How can I solve this problem? best regards

You will need to supply a flight log for anyone to be able to find a reason.

There are many factors that can cause this, radio, battery, fence,

thanks I found it reason of the GPS does not work properly…