Apple regularly releases updates to i OS that are designed address incompatibilities. To check for i OS updates: Your phone's Network Settings contain all kinds of information, including connection data and preferences for cellular and Wi-Fi networks.Check to see if an i OS update is available for your device. If one of the Wi-Fi settings is corrupted, it can prevent you from getting on the Wi-Fi network.
I also went through the activation process on my verizon account 3 times... If you're having issues with your phone or device, visit our Troubleshooting Assistant.
In this case, the solution is to reset the network settings, although this deletes some preferences and stored data related to connectivity.
You may have to ask the owner of the network for the connection data and enter it again: Your i Phone does a lot of things designed to make it useful.
If none of these solutions have helped, you'll need to take a drastic measure: restoring your i Phone to its factory settings.
This deletes everything from the i Phone and returns it to its out-of-the-box pristine condition.