Cant "calibrate accel"

I use Mission planner 1.4.77 and when i click “calibrate accel”, it says “place vehicle level and press any key” and then i click it and nothing happens and eventually it says “calibration failed” idk whether my apm or gps was the problem or i need to do something about it…please help…

Not enough details to help you.

what flight controller?
what firmware version?

GPS plays no role in accel calibration, only on compass calibration.

APM? Do you the APM Flight Controller that hasn’t been supported for years?

I use ardupilot mega apm 2.8 and im new to this…right now im building a hexacopter

That board has been deprecated seven years ago. Almost no forum users use it anymore.

Try using a seven years old mission planner.

It’s probably most advisable to update your hardware to an STM32F4, F7, or H7 based autopilot and use a recent, stable release of all firmware/software.