Email authentication is needed to verify the identity of the email sender in order to confirm that the sent email comes from the right source - the one which is listed as the sender.
Setting up Domain Authentication
You can set up domain authentication in your account, in the section "Email Authentication".
STEP 1 You will need to enter the domain for authentication.
STEP 2 After entering the domain, a page with three entries will appear - DKIM, SPF and DNS verification.
STEP 3 To successfully complete the authentication, you need to add all these entries to the domain zone.
If there is a person in charge of editing the site or receiving mail (domain hosting or IT team), transfer the record data to them to do the record adding.
STEP 4 After adding records to the domain zone, go back to the page where you received the entries and click the "Verify Records" button. If everything is correct, the status of the records will change to "Record is confirmed".
STEP 5 Authentication was successful if SPF, DKIM, Sender ID and Verification were marked "Verified"
If the domain doesn't get verified with the first try check the most Common Mistakes in Email Authentication