apple id says email is not valid
I'm trying to get into last year's ipad. I reset the password on my apple ID, and can log into iCloud with the ID and password... but the next screen asks me to verify it. I try to enter the verification code, and it says the eMail is not valid as an apple ID. (It is a gmail account.) I don't know how else to verify the eMail, or why it says that my apple ID email is not valid. Appreciate the help.
Thanks.