Imessage and facebook will not activate

I have changed my apple ID password, and since then my imessage and facetime will not activate, it says: "Could not sign in. Please check your network and try again." My internet connection is fine, my username/new password have been entered correctly, my time/date are correct, I have the latest software installed, and I have turned it on and off again, yet the same problem keeps arising.

Could anybody help (I have the iphone 5, if this helps).

Thank you in advance.