iOS 15

Hi I downloaded iOS15 to my iPad and now I can’t connect to the internet. I can connect on my phone and another iPad so the connection is working. I have tried resetting the network settings, hard rebooting, restarting the router, forgetting the network and reinstating it. Nothing has worked. The iPad is showing the home Wi-Fi network name but it says underneath ‘no network connection’. How do I connect to the internet ?