Push Notification Problem

Since updating my iPad to IOS8.3, push notifications have stopped working. Affects Apple and third-party mail clients. Running mail produces a message "Connect to iTunes to use Push Notifications". I have connect to, and re-synced with, iTunes but the problem persists, in fact the error appears before I connected to iTunes, after connecting or, even, whilst connected. In iPad Settings the apps appear to be correctly set to generate the notifications

Anyone else experiencing this, or have any idea how to solve it?