Updated: 28 September 2026 · Applies to: cPanel & WHM 138 (WHM, root access)
If one cPanel account on your server is sending spam (often because a mailbox password or website was compromised), stop its outgoing mail first, then find and fix the cause.
Stop outgoing mail for an account
whmapi1 suspend_outgoing_email user=USERNAME # reject new outgoing mail whmapi1 hold_outgoing_email user=USERNAME # or keep it in the queue for review
Undo with unsuspend_outgoing_email or release_outgoing_email. In WHM you can do the same in Account Functions › Manage Account Suspension.
Find the source
- Email › Mail Delivery Reports in WHM shows which account and address sent the most mail.
- Change the passwords of affected mailboxes, and check the website for malicious scripts.
- Clear spam left in the queue with Email › Mail Queue Manager.
Prevent it
In Server Configuration › Tweak Settings, limit how many emails per hour each domain may send, and keep spam filtering on for incoming mail.
