1. Confirm the Email Address

• Verify that the subscriber’s email address is spelled correctly in the subscription request.

• Check for common errors (extra spaces, missing periods, wrong domain, etc.).

2. Check Subscription Status

• Confirm if the subscriber is already subscribed to the list.

  • For Dynamic/Smart lists use the command line in list manager and type the following: REVIEW listname (RCPT NOH MSG ALL TOPICS BY NAME

• Look for pending confirmation requests (if double opt-in is enabled).

• Verify if the address is on a suppression list (e.g., previously unsubscribed, bounced, or blacklisted).

  • Log in to the LISTSERV web interface with your list owner credentials.

  • Navigate to your list management dashboard.

  • Look for the “Subscriber Management” section.

  • Search for the email address in question.

    • If the address does not appear as an active subscriber but has a status message like “Bad Address”, “Bounced”, “Deleted”, or “Hold”, it may have been automatically placed on the auto-delete/suppression list. Please reach out to your listserv administrator for additional support.

3. Review Delivery Logs

• Determine whether the message was:

  • Delivered successfully

  • Deferred or delayed

    • Log in to the LISTSERV web interface with your list owner credentials.

    • Navigate to your list management.

    • Select List Activity Reports

4. Check Moderation and List Settings

• Ensure the subscriber’s request or the message to them was not:

  • Held for moderation

  • Blocked by list policies (e.g., restricted senders)

  • Sent to a digest (delaying immediate delivery)

5. Inspect Bounce or Error Messages

• Look for bounce notifications tied to the subscriber’s address, these will be emailed directly to the list owner

• Identify common reasons:

  • Mailbox full

  • Invalid domain or recipient not found

  • Rejected by the recipient’s mail server (SPAM or policy filters)

6. Check Email Filters and Spam Folder

• Ask the subscriber to:

  • Review their spam/junk folder.

  • Add the list’s sending address to their contacts/whitelist.

  • Check whether their organization blocks bulk or automated messages.

7. Test with Alternate Addresses

• Try sending a test message to the subscriber from outside the listserv system.

• If that fails, the issue is likely with the subscriber’s mail provider.

• If successful, the problem is specific to the list system.

8. Escalate if Necessary

• If list activity show delivery attempts but the subscriber still cannot receive:

  • Contact the listserv administrator for deeper log analysis.

  • Provide timestamps, the subscriber’s email address, and any bounce/error codes for further investigation.

  • Listserv administrator can be reach by submitting a request to either option below:

    • Report an Issue

    • Email

✅ Tip for List Managers: Always document what steps were taken so recurring issues with the same subscriber can be tracked and resolved more quickly.