Apm 2.8 I need HELP

Hi there! I’m building my first dron. Im using an APM 2.8 and mission planner. I can’t calibrate accel it says FAILED. I’ve tried a lot of times and nothing new happened. I’ve desarmed my dron and left alone my APM nothing happened. I’m thinking flight controller is not work. Anybody could help me?

APM is no longer supported you will need to use an old version of mission planner to get compatibility.

Which version do you recommend?