Hello,
Do you have internet access, when connected to the Iphone wireless network only?
Do other devices connect to the internet, when connected to the Iphone?
Also, I would like you to change your LAN IP subnet before connecting to the wireless WAN source. Go to Network -> Interfaces. Edit LAN settings. Set IPv4 address to, for example, 192.168.128.1.
Best regards,
Žygimantas