iPhone says my domain is not secure
When I type in my domain, I get a message that it is not secure. I do not get the message with Android or PC
[Re-Titled by Moderator]
This means that the settings of your router are not up to the latest security settings. You can check your router manual or go to the website of your router's make and model to learn how to change these settings. If your router is combined with your modem, you will need to check with your service provider.
Recommended settings for Wi-Fi routers and access points - Apple Support