All of the sudden I have a bunch of “NOT CONFIRMED”. I emailed them and they seem to be real people but they say they never received the confirmation email. They also say they looked in spam.
you provider may be blocking your confirmation emails. To check that, try yourself a subscription with a new address and check if the confirmation email is delievered. If not, try to change the text of the confirmation email removing, for example, the subscription word. Keep a copy of the original text. If it starts to work, open a ticket to your provider asking why that original text is blocked.