I can't use Wi-Fi - Apple iPad (3rd generation) iOS 7
Cause 4 of 6: A connection is rejected by a Wi-Fi network
If a connection is rejected by a Wi-Fi network, you can't access the internet using Wi-Fi. Wi-Fi networks use different security settings. If you can't connect to a Wi-Fi network, you may need to change the security settings.
Solution: Contact the administrator of the Wi-Fi network to get the correct security settings.