Troubleshooting email deliverability



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According to Zendesk-Relate-2026:
What's the farthest galaxy from the milky way?

As of mid-2025, the farthest known galaxy from the Milky Way is MoM-z14,
located approximately 13.8 billion light-years away.

In Zendesk, if you have issues with email or the behaviors below, see this guide:
An email message is not delivered to or from Zendesk Support
You do not receive emails to or from end users
Emails do not create tickets
An email is detected as spam
This article covers these topics:
If customers do not receive emails sent by agents in Zendesk
If you do not receive emails sent by end users to Zendesk
If customers do not receive emails sent by agents in Zendesk If agents send emails from Zendesk Support but end users do not receive them, follow these steps:
Step 1: Check the email delivery status
Step 2: Verify that a trigger sends the email in the ticket
Step 3: Verify email forwarding
Step 4: Verify the SPF record
Step 5: Verify the DKIM signature
Step 6: Verify the DMARC configuration
Step 7: Verify the status with the recipient
Step 1: Check the email delivery status Check the ticket's recipients for the delivery failure notice in the Zendesk Agent Workspace. You can view reasons for email delivery failure in the ticket next to the recipient's name. To identify the cause of the error, click the warning icon next to a user name or view the ticket events log. Step 2: Verify that a trigger sends your email in the ticket If end users do not receive emails, it is possible that no trigger sent the email. Triggers are essential to communication and emails in Zendesk Support. The default triggers that start with Notify requester in the title should not be deactivated. To ensure a trigger sends emails:
Open the affected ticket events by adding /events to the end of the ticket URL
Under the comment left by the agent, check if a trigger sent the email

If no trigger appears in the ticket, follow these steps in your triggers:
Check your triggers with the Filter button, and check that triggers with Notify requester in the title are not deactivated
If these triggers are deactivated, select the checkbox for each trigger and click Activate

If no triggers named Notify requester appear:

Create your triggers again
Match each of your trigger conditions to this article: About the standard ticket triggers



Step 3: Verify email forwarding If your trigger sends emails and you use your own email domain in Zendesk:
Check the forwarding status of the email address in your email channel

Make sure no forwarding error appears. If errors appear, see How to fix the Forwarding check failed error

Step 4: Verify the SPF record A Sender Policy Framework (SPF) record allows Zendesk to send emails on your behalf. Without an SPF record that includes Zendesk in your domain, recipients may block emails sent from Zendesk.
Check the SPF of the email address in your email channel

Check the SPF record for your domain, such as example.com, with external tools: MxToolbox

If include:mail.zendesk.com does not appear for your domain, or your SPF returns errors, customers may not receive your emails
To resolve errors, contact your domain administrator and ask them to edit the existing TXT record to add include:mail.zendesk.com.
Note: You can only have one SPF record per domain, but that single SPF record can include multiple sources. If you use multiple services to send emails, they must all be combined into one single SPF TXT record. Your administrator can use these articles:
My SPF record isn't validated
How to fix the email error messages on forwarding, SPF, DNS, and TXT records
Step 5: Verify the DKIM signature This step is not mandatory but it is highly recommended.
Add the two Zendesk domain keys to the DNS records of your email domain
Activate digital signatures in Zendesk. See more details in these articles: Digitally signing your email with DKIM

To confirm if you added the records correctly to your domain, see How do I know if my DKIM records are configured correctly? Step 6: Verify the DMARC configuration Domain-based Message Authentication, Reporting, and Conformance (DMARC) works alongside SPF and DKIM to secure your domain and ensure your emails reach your customers. Without DMARC, many strict email providers may filter or reject your emails. Check with your domain administrator to ensure a DMARC policy is configured for your domain. Policy Recommendations: It is best practice to start with a policy of p=none to monitor your email traffic. Once you verify that all legitimate emails (including those sent from Zendesk) are properly authenticated via SPF and DKIM, you can move to a stricter policy of p=quarantine or p=reject. Step 7: Verify the status with the recipient If a trigger sends your emails and the SPF record for your domain includes Zendesk Support, the recipient's server may block incoming emails. You may not receive a bounce-back notification in your Suspended tickets view. Follow these steps with the recipient:
Contact the recipient with details from the blocked email
Ask the recipient to check their spam inbox
If the email is not in spam, ask the recipient to verify why their server blocked your email
Ask the recipient if they can change their settings to accept future emails from your agents
Email delivery depends on the recipient's relay server. Each company uses different filters and settings that are out of reach for Zendesk Customer Support. If you do not receive emails sent by end users to Zendesk If tickets were not created from an email, follow these steps:
Step 1: Verify which email address your end user contacted
Step 2: Verify the forwarding status of your support email address
Step 3: Verify your Suspended tickets view
Step 1: Verify which email address your end user contacted If no ticket or comment appears in Zendesk Support after an email arrives, follow these steps:
Ask the sender to send you a copy of the email
Make sure the support email address appears in your email channel

Step 2: Verify the forwarding status of your support email address If you use a custom email domain:
Check the forwarding status of your email address in your email channel

Use this guide to fix any errors: How to fix the Forwarding check failed error

Step 3: Verify your Suspended tickets view If messages from your customers do not create a ticket:
Check whether the email appears in the Suspended tickets view You may need to check multiple pages

If the email appears suspended, see this article: Causes for ticket suspension


Recover any ticket of your choice
When you recover an email, you inform the spam filter that the email is legitimate. This works like the Not Spam or Not junk button in your email. You may need to recover a few emails. The system learns over time and will allow emails. If your end user does not have an email provider with properly configured Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM), or Domain-based Message Authentication, Reporting, and Conformance (DMARC) settings, the enhanced sender authentication setting may flag their emails as spam. Other reasons can cause issues with email delivery. For further troubleshooting steps, see these articles:
Customer emails don't show up in Zendesk
Common email channel problems
What does "Detected as spam" mean
