When adding a new from address to your account, you'll first need to verify that it's hosted at a domain you have permission to use. This helps your sender reputation by ensuring your domain can only be used by an account that has permission to do so.

You only need to verify a domain once. Then you can use it for any email address at the verified domain.

How to Verify a Domain

1. Go to Account -> From Addresses
2. Click Verify Domain from the top toolbar buttons
3. Enter an email address with a domain you want to validate. We will send a verification email to that address with a link to verify the domain for use with from addresses.
4. Click Submit
   1. If you enter an email address and it's already verified, a message will appear saying "Domain is already verified." No further action is required.
5. When you receive the email message, click the Verify Domain link 
6. Once you verify the domain, you'll be able to add from addresses at that domain

Before Sending

We highly recommend that you verify and authenticate domains before sending from them. Authenticating email from your domain helps protect your brand by reducing the chance that your email is mistaken for spam. It also helps build and maintain a good sender reputation by providing a digital signature that authorizes each email as coming from you. Learn more.

FAQ

• You may not use any "free" email addresses as your From Address, i.e. @aol.com, @hotmail.com, @gmail.com, @yahoo.com, or any other email address that does not accurately reflect the identity (sending domain) of your company or attempts to hide your identity from recipients. Your email may be rejected/bounced if you use these free email providers as from addresses. All DMARC compliant mail receivers (Yahoo, Hotmail, Gmail, etc) are bouncing emails that are sent with these from addresses (@yahoo.com, @outlook.com, etc) but are not sent through their servers.
• If you haven't received the "Please verify your domain" email, it may take a few minutes to send. You should also check your junk folder, to see if it landed there. 
• You can retry sending the message after about 5 minutes.