FaceTime Activation message on iPad 4th Gen

I cannot log in to iMessage on my 4th Gen iPad. On each login attempt, after several minutes I get "FaceTime Activation Unable to contact the FaceTime server. Try again. I have confirmed the date/time zone (set to automatic) is correct, and cycled this as well. I have confirmed my apple id and password are correct and I have logged out of iTunes and back in. I have shut down my iPad and restarted it. The software is up to date. I just FaceTimed with my grandson this morning on my iPhone, and I am able to send iMessages on my iPhone and my iMac without any problems. Can anyone help with this problem??