This is only known to occur when entering a customer or email that already exists in your Offers account.
If you are trying to enter a new fan into the fans table and the system is displaying a notice at the top of the page that says "This fan already exists." OR you conduct a search and do get a returned result, then this fan record is either Opted-Out or Archived by you.
Click the Lists drop down and check in these lists to find their name or email. If the customer is in Archived, then you can move them back to 'All'.
Trouble logging in? Simply enter your email address OR username in order to reset your password.
For faster and more reliable delivery, add firstname.lastname@example.org to your trusted senders list in your email software.