Hello @DebbieH954 ,
Our main article on self-authentication provides the steps by which domains are self-authenticated for accounts.
Your main issue however, would be in regards to the email addresses themselves. If you're using email addresses that don't actually exist or can't accept emails, the ability to verify them is going to be more difficult, or simply impossible. Email addresses, regardless of your account's self-authentication status, must be verified before they can be used for account addresses- including your From and Reply-To addresses. If anything, I would recommend speaking directly with our Delivery team for insight into your specific situation.
See also:
Email Authentication FAQ
... View more
