Apm 2.6 Ignores mav_frame_local_ned

Hello, currently I am using apm with a rapsberry pi and do missions with dronekit python version.There is no problem when taking off and rtl mode but when I try velocity command drone does not move at all while flying.Anyone has an idea?

That version is very old and probably does not support that mavlink message.
Either update the hardware and firmware to 3.6.9 or implement that function in the software and recompile.