Use the mail delivery log in cPanel to see what happened to a message.
- Log in to cPanel and open Track Delivery (under the Email section).
- Enter the recipient address in the Email box and click Search, or just run a report.
- Review the results: green means delivered, red means it failed.
- Click Details on a failed line to read the exact error, such as mailbox full, user unknown, or a remote server rejection.
The error message usually tells you the cause. If it mentions a blacklist, spam score, or your IP being blocked, please open a ticket with the recipient address and the error text so we can investigate.
