Overview: When managing a VPS, ensuring that your emails don't end up in the Spam folder is critical. This is achieved by proving to receiving servers (like Gmail or Outlook) that your VPS is authorized to send emails on behalf of your domain using three main records: SPF, DKIM, and DMARC.
Steps to Enable Email Authentication:
Log in to WHM as root.
Search for "Email Auth" or "Manage Customizations" in the sidebar.
For a specific account, go to "List Accounts", click the cP icon to enter the cPanel of that user.
Inside cPanel, search for "Email Deliverability".
You will see a list of domains. If any show a "Not Valid" status, click "Repair" or "Manage".
SPF & DKIM: The system will automatically generate these records. Click Install to add them to your DNS zone.
DMARC: This is an extra layer of protection. It tells servers what to do if an email fails the SPF/DKIM checks (e.g., Reject it).
Pro Tip: Use the "Mail Delivery Reports" tool in WHM to track any emails that failed to deliver and see the exact error message provided by the receiving server. This is the fastest way to troubleshoot "missing" emails.