These are the steps I've used to pair everything successfully when the standard instructions failed.
The individual steps each have YouTube videos and instructions on this Forum if you use the Search tool...
Perform factory reset on both aircraft and remote.
With remote off connect aircraft directly to phone in wifi settings.
With aircraft off connect remote directly to phone in wifi settings.
Perform pairing operation between aircraft and remote.
Turn off both devices and close DJI Go 4 app. When you turn everything back on all 3 devices should now connect automatically.