Public wifi is in most places these days and there are security risks to connecting to these, however, they are still a convenient method to stay connected. This is especially useful if your in a large building where LTE connection is non-existent. To access Wifi users simply connect to the wifi and in most cases, the captive portal appears to verify that you can, in fact, connect to the internet and then you are good to go. There are in some instances where this just doesn’t work.
To try an overcome this go to Tap Settings > Wi-Fi and make sure that Wi-Fi is on. Tap the name of your Wi-Fi network to join. A blue checkmark beside a network name means that you’re connected. If you see Auto Join Disabled under your Wi-Fi network name, tap it turn on Auto-Join. If asked, enter the password for the Wi-Fi network.
Sometimes the error can be that if you are trying to connect to google or yahoo because these use HTTPS and the wifi can sometimes not match the security certificates. To resolve this you need to go to Never SSL. never ssl say they will never use SSL (also known as TLS). No encryption, no strong authentication, no HSTS, no HTTP/2.0, just plain old unencrypted HTTP and forever stuck in the dark ages of internet security.
No Internet Connection Error
If iOS detects an issue with your Wi-Fi connection, you might see a Wi-Fi recommendation under the name of the Wi-Fi network that you’re connected to. For example, you might see the alert “No Internet Connection.” To get more information, tap the Wi-Fi network.
Try restarting your iOS device. After you restart each device, see if you fixed the issue. If you still cannot connect, Reset your Network Settings. Tap Settings > General > Reset > Reset Network Settings. This also resets Wi-Fi networks and passwords, cellular settings, and VPN and APN settings that you’ve used before.