Zoho Desk can alert you to email delivery problems so you catch and fix them before customers notice. This guide shows you how to access failure notifications and retrieve the technical details needed to troubleshoot.
Why this matters
Email delivery failures in Zoho Desk prevent tickets from being created, delay customer responses, or cause messages to land in spam. Without visibility into these failures, support teams waste time wondering why customers haven't heard back. Setting up failure alerts lets you spot authentication issues, bounce problems, and delivery delays quickly and respond with corrective action.
Step-by-step
Step 1. Navigate to the Email Failure log.
In Zoho Desk, go to Notifications > Email Failure. This section displays all outgoing and incoming email issues your system has encountered [1].
Step 2. Review the failure entry.
Select the failure entry you want to investigate. The log will show you the type of failure—whether it's an incoming email that didn't create a ticket, a delivery delay, a bounce, spam classification, or an authentication failure (SPF, DKIM, or DMARC) [1].
Step 3. Report the failure if needed.
Click Report email failure to escalate the issue for further investigation. This creates a record that helps your team track patterns and identify systemic problems [1].
Step 4. Retrieve email headers for diagnosis.
To dig deeper into a specific failure, locate the email in Zoho Desk and open its details. Click Show Original, then click Download Header to save the email header file [1]. Email headers contain sender and recipient addresses, subject line, timestamps, mail server information, and authentication results—all essential for tracing where the email broke down [5].
Step 5. Share headers with support if needed.
If you're using Custom SMTP or Modern Authentication, Zoho Desk cannot capture full delivery logs because emails go directly through your configured SMTP server. However, email metadata (sender, recipient, subject, timestamp) is still available [1]. Share the downloaded header file with a support representative to accelerate diagnosis.
Common pitfalls
If you've configured a custom SMTP server, be aware that delivery logs won't be captured by Zoho Desk itself—only metadata will be stored [1]. If your SMTP provider has rate limits (for example, 500 requests per day), emails exceeding that limit will fail silently and fall back to the default Zoho server [3]. Check with your SMTP provider about any restrictions they enforce.
If you're using email routing and want senders to receive bounce notifications when delivery fails, you must enable the Send bounce when mail to the destination fails option in your Email Routing settings [4].
What to check
- Confirm that Notifications > Email Failure is accessible and showing recent entries.
- Verify that you can download email headers from failed messages and that the header file contains authentication and routing information.
- If using custom SMTP, confirm with your provider that they're not blocking requests or enforcing daily limits that would cause silent failures.
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*This article is provided by Beam Help — independent expert support for Zoho. We are not official Zoho support.*