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It sounds like Keychain is causing this issue. First we can reset your iPad and see if it works or not. Press and hold down the Power button and Home button at the same time until it shows the Apple logo. When you see the Apple logo, release the buttons and let it boot.
Note : Power button is the button you use to turn off your iPad or its screen. Home button is the round button at front bottom.
Now setup your iPad again by following onscreen instructions. When you get to the stage where it asks about Keychain, select Do not restore passwords and continue without using Keychain. This will allow you to setup the iPad without that step.
Please let me know if that didn't work, so we can continue troubleshooting.