If you already own a domain, we need to confirm it's yours before we can add it to your Pobox account.
If you use it for email, DON'T DO THAT! It could make email for your domain bounce while you get your addresses set up. Instead, just submit the Add Domain request. We will try to confirm it by sending a message to the admin contact on your Whois record or, if that is private, sending you a secret code to add to the root web page for that domain.