The domain authentication is a great way to increase your inboxing and stay away from spam folder.
To authenticate your domain, you need to follow the simple easy steps:
Go to account > sending emails or Click here
You need first to add new email (Note: you need to use an email like: [email protected])
Verify your email
Once verified, click on the button "Authenticate" then a new popup will be displayed (see below)
There are 3 txt records that you need to add to your domain hosting (dns zone): DKIM, SPF, and DMARC
Copy each text record with the value in your domain dns zone (Note: You can ask the help from your hosting provider is you're not familiar with dns records)
Once done click on the button "Check DNS records" (Note: It takes up to 48 hours for dns to propagate)
If verification fails, just give it some time and try again
If you point your domain to a CDN like cloudflare, then you need to add the dns records above on dns area in cloudflare.