iPad won't send messages after restore

Recently restored my iPad gen 6 to factory to possibility solve a battery issue. Battery issue remains unsolved (draining from 100% to 0% in under 10 minutes) but now I can no longer send text messages from the iPad. Getting the red exclamation point with "This iMessage was not delivered". Steps I've tried:

1) Restored again to factory reinstalled from the Cloud

2) Logged out of my AppleID acct and logged back in after a restart

3) Tried sending texts to multiple recipients

4) Updated to the latest iOS

5) Turned iMessage off, restarted and turned it back on

6) Doubled checked the acct info is correct under send and receive

Messages can be sent fine from my MacPro and I can see replies on both my Mac and the iPad but can only reply on my Mac.

As stated, all this started after a restore from an icloud backup from factory.

Any help would be greatly appreciated. Thanks in advance!!