iMessage won't activate

Hello,

I have a number of iOS devices that I cannot get iMessage to work. It seems to be a fundamental problem with my appleID as opposed to an issue with the devices, as I can get the devices to work with OTHER apple ID's, just not the apple ID that i want. Note that the apple ID i'm trying to make work worked for many months prior, and as of yesterday, signed me out of all my devices, and won't let me login anymore.

I've got an iPhone 6 version 9.2.1

iPhone 6 version 9.3.1

iPad air version 9.0.1

iPad air version 9.0

I've got about 15 other iPads but i haven't bothered booting them all up to test this as I couldn't get it to work on the first 4. Again my iMessage works fine with my other apple ID, but not the one i want to work. Any advice on what else to try?

I've followed basic steps through the "can't login article",

Which did not resolve the issue. I've done the other basic trouble shooting such as turn off, restart, turn on. Full data wipe. Using wifi or my 4g connection.

I am at a loss!

EDIT: I Should also note that iMessage does work through the phone number on the 2 phones. I can also login with the apple id into the app store and download apps. It just gives the "can't login, try again later" when i try to sign into imessage / facetime. I can login with the different appleID without issue and then immediately log out, try with the one i want, and it errors.