There is no WiFi SSiD listed when the app is launched. I've tried renaming it and force searched for it from my WiFi setting on my iPhone. Still no luck.
On a P3S remote, you don't need the Phantom or the DJI-Go app.
You can see and connect any device to the remotes WiFi, yes even a laptop, try-it.
The WiFi signal from the remote is the same as any AP. If a mobile device doesn't see it, its not there.