Wifi connected but doesn’t work

Are you on a public network, by any chance? Like a hotel? If you are on a public network, you will need to visit that network's portal screen first. Open Safari and you will be taken right to the page that asks you to agree to their Term and Conditions. Once you do that, your WiFi connection will be permitted to connect to the outside world.

Try to turn on airplane mode for 15 seconds then turn it off and see if it connects.

If the issue persists sometimes you need to restart your router. Your other devices may not be experiencing issues but sometimes the router will have issues communicating to another device.