Email verification issues imessage

After reformatting a used iPad, everything works fine, EXCEPT trying to sign into iMessage.

THe email address which has been verified for the user, including the password as an apple ID functions when signing into the app store or iCloud but won't be accepted when trying to open iMessage.

WHen I use my own apple ID, I can open iMessage with no problems yet when using the owners info, it won't verify.

IVe spent 5 hours today searching for answers and tried every suggestion I could find online-but to no avail.

IT seems to be a real anomaly or I'm just missing something rudimentary.

PLease excuse the typos but I'm very tired.

SUggestions anyone?