Once you have connected your phone to the OS2's own WiFi AP (solid white LED) you don't have internet access yet, so you need to try connecting to
http://openspot2.local
and if that doesn't work then try the 192.168.99.1 IP address.
You can then set up the OS2's country settings and tell it your home WiFi details, the sharkrf.link address only works once the OS2 is connected to your WiFi router and thus has internet access.