Overview
An admit alert workflow is triggering correctly and the CRM logs the email as sent, but the recipient email address never receives the email. The issue persists even after the recipient's IT team has confirmed that [email protected] is whitelisted and not blocked on their end. The emails are not appearing in spam or junk folders, and the recipient's mail server shows no record of the message arriving at all.
This behavior is caused by Mailgun bounce suppression. When a previous email to the recipient address bounced, Mailgun automatically added that address to its suppression list. All subsequent sends to that address are silently blocked by Mailgun before the message ever reaches the recipient's mail server — with error code 605: "Not delivering to previously bounced address".
Because the CRM records the email as sent and Mailgun suppresses it silently, this issue can be difficult to detect. Whitelisting [email protected] on the recipient side has no effect, because the emails are never transmitted to the recipient's server in the first place.
Possible Causes
A previous email sent to the recipient address (for example, a group inbox such as an admit alert distribution address) bounced for any reason — including a temporary server error, a size limit rejection, or a misconfiguration at the time.
Mailgun recorded that bounce and added the address to its suppression list.
All subsequent workflow emails to that address are rejected by Mailgun internally with error code 605 and never leave the Dazos sending infrastructure.
Solution
Contact Dazos Support. End users and IT teams cannot clear Mailgun suppression entries directly. You must contact Dazos Support and request that the affected email address be removed from the Mailgun suppression/bounce list.
Provide the affected email address. When contacting support, include the exact email address that is not receiving workflow emails (for example, a group or distribution inbox address). If you have access to any workflow logs or CRM activity records showing the email as triggered, include those as well.
Dazos Support checks Mailgun suppression logs. The support team will review Mailgun logs for the affected address and confirm whether a suppression entry exists with error code 605 ("Not delivering to previously bounced address").
Dazos Support clears the suppression entry. Once confirmed, the support team will remove the address from the Mailgun suppression list on the Dazos side.
Test delivery after the suppression is cleared. After Dazos Support confirms the entry has been removed, trigger a test workflow to the affected address and confirm that the email is now received. Monitor for successful delivery in the CRM activity log.
Still Need Help?
Contact Dazos Support if:
Workflow emails to a specific address stopped arriving suddenly, even though the workflow is active and conditions are met.
The recipient's IT team confirms no email is reaching their mail server at all — not even a rejected or bounced message.
You have already confirmed the address is correctly listed in the workflow and the workflow is triggering as expected.
The issue persists after Dazos Support has cleared the suppression entry.
When contacting support, please provide:
The exact email address that is not receiving workflow emails.
The name of the affected workflow.
Confirmation that the recipient's IT team has checked their mail server logs and sees no incoming messages from [email protected].
Any CRM activity log entries or screenshots showing the workflow was triggered.
Important: Whitelisting [email protected] as a safe sender on the recipient's mail server will not resolve this issue. The suppression must be cleared within Mailgun on the Dazos side. Only Dazos Support can perform this action.