I've seen some discussions on this before, but still couldn't resolve the issue. I want to use Return To Controller feature. When I try to set/refresh my controller location thru the 3-dots settings on top right, it always say cannot get GPS info. So on my screen, the distance from drone to controller always show N/A. But when I playback the flight record, it shows my controller location fine.

I'm using iPhone 7 plus and GPS is working fine (tried Apple Map & Googlr Map before DJI Go app). I tried several locations (park, beach, hiking trail up on the mountain) nothing works. Am I missing some settings to turn this feature on?

have you tried plugging phone to the USB underneath with your apple USB cable instead (leaving the short side one unplugged) and putting phone in airplane mode ?
I use iphone 7 that way and i dont have this issue, it could be + related but maybe worth a try for you ?