Changed AppleID Password and now iMessage and Facetime get Activiation Errors only on 1 of 5 ipads

I have an appled ID in the proper format XXX@gmail.com.

When trying to login to "manage my appleID", I was forced to change my password to a "stronger password" which I was trying to avoid since I had so much attached to that AppleID that I thought I would run into all kinds of problems synching all the new passwords, and OF COURSE I did... ( stupid apple for making me do that !!!!!! )

NOW... here's the problem.. I had to go back on all of my devices and get things all synced up again. 1- iphone, 5 ipads, 2 itouch

I know that each of us could have our own appled ID, etc. etc... but that wasn't the way it was set up when we originally got our products, and when you have children using these, it was just easier to sign them all up under my AppleID. And I have no desire to go back and change things now, who has the time for that ??

My question is.. ONLY ONE of my iPads ( that has IOS 8.1.2 ) can't get iMessage and Facetime set up properly. ( the rest I've gotten to work now properly )

When I attempt to go to settings, and click on Messages or FaceTime I get a screen that has my Apple ID prepopulated .. the password field is blank.

When I enter my newly change Apple ID password, I get an error

iMessage Activiation An error accurred during activiation. Try agin. OK

I can't turn anything iMessage or Facetime on and off, because this is all I get, I don't get the option...

If I access Message or Facetime directly.. I get a similar login screen, resulting in the same error.

I've tried rebooting my ipad and waiting a few hours and trying again. Still no luck.

I have a strong wifi connection and get to the internet just fine.

I've tried resetting network connections via Settings, General .. no luck.

I've all tried resetting "all settings", with no luck.

It seems icloud can see the ipad just fine, and I can send a lost signal to it.

Any advise ?????? What am I missing... ?? all other 7 devices I got working just fine, so I seem to know somewhat I'm doing.. but I'm stumped ?? Something must have got hosed that I'm missing on this one..

Everything else seems to be working just fine, email, internet, etc. Thank you !!