Manage spam filtering and recover wrongly filtered messages

Spam filters evaluate incoming mail and may mark it, move it, reject it, or remove it according to the configuration. Review the action as well as the sensitivity. A very aggressive filter can hide legitimate messages from customers or automated services.

Control Center's Email page does not edit spam-filter rules. Use Open webmail to review folders and available personal rules. For permitted domain-level filtering controls, choose Open Virtualmin and select the affected domain.

1. Check the mailbox's Junk or Spam folder before changing anything. Search by sender, subject, and date, and review any personal rules that move messages into other folders.
2. If a legitimate message is present, mark it as not spam using the mail client's controls. Whether that action also trains the server's filter depends on the configured service.
3. If your Virtualmin account exposes Spam and Virus Scanning, open it for the correct domain. Record the current settings. Virtualmin supports domain filtering choices, but availability and delivery actions depend on the installed features and permissions. Virtualmin spam and virus scanning
4. Prefer a reviewable spam folder while adjusting sensitivity. Change one setting at a time and observe the results before making another change.
5. Add a narrow sender allow rule only for an address you trust, if this feature is available. Broadly allowing an entire public email domain can admit unwanted mail. An allowed address can still be spoofed or compromised.
6. Check mailbox storage and retention rules. A large spam folder can consume space, but emptying it permanently may remove a message you need. Review before deletion.

Check the result: Ask the affected sender to send a new plain-text test message. Record where it arrives. Keep the original message's headers if the issue persists; they can show filtering results that are not visible in the message body.

Common problems: Desktop filters, webmail filters, and server filters may all act on the same mailbox. A rule fixed in one app may not change another layer. Messages rejected before delivery will not appear in Junk; request the sender's delivery failure notice. Server-wide filter installation or configuration requires support and is not a domain-owner task.

Report suspected phishing without opening attachments or replying. Spam scanning does not replace careful handling of unexpected payment or password requests.

Related: Webmail, Email authentication, Delivery failures.