By default, if a referral link gets more than 500 signups, it will be marked as spam and the link won’t work any more. If you want to allow “unlimited” referrals from a specific referral link, you must do the following:

Next, put in the email addresses (1 per line) for each person who is sharing a referral link. This should be the email of the person who entered the giveaway and is sharing their referral link.