iOS App - Save Button is grey for setting an IP/Host

[Dragontorc]

Downloaded app to both my iPhone and iPad. Tried with mobile data disabled using both devices with no luck. The SAVE button for IP address stays greyed out (in both cases when IP address or http://MiSTer.local:8182 typed in the field). Script is running on the MiSTer device and I'm able to connect by typing IP address and port of the Mister in the web browser (works on both mentioned above devices).