From Domains

From domains

In order to start sending emails, you have to verify your domain by createing a few DNS entries. These DNS records are necessary to let mailboxproviders know that the mail is really coming from you. This means that you should also keep these DNS records after the validation process. This seems like a lot of work to start with but unfortunately, it's really necessary. If we would let you send without the domain verification, a lot of your email would be blocked or end up in the spam folder.

When your domain is verified, you can use every email address you want without further verification mails. So if you verified you can send from all these addresses: