Are you manually focusing the lens....? If not, then forget about calibration as it won't do you any good.
The calibration process simply lets the DJI Go app determine a distant point measurement to use as 'infinity' when using the manual focus slider on screen... the slider has two icons, one for closest focus, and the other for distant focus and you can click on each icon to rapidly move from one end of the focus scale to the other... that's all it does. Closest focus is preset in the lens, but distant focus is variable as some lenses can focus 'beyond infinity' for use on ir capable cameras.
If you use autofocus/tap-to-focus then calibration isn't needed as the sensor/af algorithm does the work for you.