When a customer says "my email did not arrive", the answer is usually in the mail logs. Mail Delivery Reports in WHM shows delivery attempts for all accounts you manage in one place, so you can search by sender, recipient or time without opening each cPanel.
Before you start
- WHM access. Resellers see reports for their own accounts if the privilege is enabled; otherwise use Track Delivery in each customer's cPanel (see Track Delivery in cPanel).
- The sender, recipient and approximate time of the message.
Search the reports
- Go to WHM → Email → Mail Delivery Reports.
- Set filters: sender, recipient, date range, and result type (success, deferred, failure, in progress).
- Click Run Report.
- Click the info icon on a row to see the full delivery path and the remote server's response.
Read the results
| Result | Meaning | Typical fix |
|---|---|---|
| Success | Accepted by the receiving server | Check the recipient's spam folder |
| Deferred | Temporary problem; will retry | Wait, or check greylisting at the remote side |
| Failure: 550 rejected | Remote server refused the message | Read the reason: SPF/DKIM fail, blacklist, mailbox does not exist |
| Failure: exceeded hourly limit | Account hit its sending limit | Check for spam, or raise the limit (see email limits) |
| Rejected by spam filter | Incoming message blocked locally | Review the customer's spam settings |
Common causes and fixes
- SPF or DKIM failures at Gmail or Outlook: fix authentication in Email Deliverability.
- Blacklisted IP in the rejection text: open a ticket; MdmHost handles IP delisting.
- Mailbox full: the recipient's quota is reached; ask them to clean up or raise the quota.
- Wrong MX: mail for the domain goes elsewhere (see DNS zones).
Tip: Copy the exact error text from the report into your support reply. It shows customers the real reason and often points to a fix on the recipient's side.
Spotting spam
A sudden list of thousands of failures from one account means it is probably sending spam. Act immediately (see security best practices).
Frequently asked questions
How far back do reports go?
Reports cover the period kept in the mail logs, typically several days to weeks depending on server log rotation.
Can I see message contents?
No. Reports show delivery metadata only, not message bodies.
Why does a message show success but never arrived?
The receiving server accepted it, then filtered it. Ask the recipient to check spam and their provider's quarantine.
Can I export a report?
Copy the results from the table, or use the command line on root servers with exim log searches for larger exports.
Why are incoming spam messages listed as rejected?
That is the spam filtering working. Check only if a customer reports a legitimate message missing.