Email Authentication (SPF, DKIM , DMARC)
Configuring email authentication is a best practice and helps getting the best results from your email campaigns. It tells Internet Service Providers that our mailservers are authorized to send mails on your behalf and that the mails are legitimate.
UPDATE FEBRUARY 2024:
Gmail & Yahoo require that bulk senders (5,000+ emails per day to Gmail or Yahoo addresses) authenticate their emails.
To avoid emails not being delivered, email authentication is either strongly recommended or required depending on your mail volume.
Choose "Sending Newsletters" under the "Configuration" tab to receive instructions for the DNS records to create and/or to check that the requested records have been created correctly.