I hope this helps someone in a similar situation;
I'm new to a Phantom 4 RTK, SDK controller with iPad air & Sitescan. Unable to connect to the RTK service while testing near my office. Turns out the iPad prefers wifi (heavily filtered) over 4G.
Switching off wifi so 4G is the only connection possible solved this.
Took me some time to figure this out, kudo's to the supplier and my IT guys.
Regards,
Bert