Your iPhone Won’t Connect to Wi-Fi
Whenever your iPhone can’t connect to your Wi-Fi, and it isn’t your router or network’s fault, you can try to fix it yourself.
Make sure everything’s connected properly. That means your iPhone’s connected to your network, Airplane mode isn’t on, and your connection is stable enough.
You can try to restart your iPhone and see if that fixes the problem. If not, you can go to the Wi-Fi settings, forget your network and try connecting your iPhone again.
If all that fails, you can go to Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings. This will delete all your settings, and you can start from scratch.