DMARC Policy 550-5.7.26 Unauthenticated email
Colleague could not receive any emails for the password resetting from Linktree.
Even contacted Linktree to re-send the mail again.
Went to check the email logs on Google Admin
Reporting —> Email Log Search
Identified that was because of 550-5.7.26 Unauthenticated email from…
Subject:
Linktree | Change Password
Sender:
bounces+111XXX-user=domain.hk@em2669.linktr.ee
Received from an SMTP server with IP address: 1.2.3.4 (TLS enabled)
550-5.7.26 Unauthenticated email from <a href="http://linktr.ee" target="_blank">linktr.ee</a> is not accepted due to domain's 550-5.7.26 DMARC policy. Please contact the administrator of <a href="http://linktr.ee" target="_blank">linktr.ee</a> domain 550-5.7.26 if this was a legitimate mail. Please visit 550-5.7.26 <a href="https://support.google.com/mail/answer/2451690" target="_blank">https://support.google.com/<wbr>mail/answer/2451690</a> to learn about the 550 5.7.26 DMARC initiative.
Required us to +spam filter with no “Authentication required”.
To set +spam filter:
- App —> Google Workspace —> Gmail —> Settings for Gmail —> Spam, phishing, and malware
- Spam: Add another rule
- Or, App —> Google Workspace —> Gmail —> Settings for Gmail —> Routing —> Manage address list
References
Error: 550-5.7.26 unauthenticated email from domain.com is not accepted...
https://knowledge.broadcom.com/external/article/216098/error-5505726-unauthenticated-email-from.html
- Confirm that Messaging Gateway is configured to sign outbound messages using DKIM
- Protocols > Domains > domain > Delivery > DomainKeys Identified Mail
- Confirm that that DKIM records are published to the DNS and are correct
- Confirm that SPF records are published to the DNS are and correct
Update
- +knowledge.broadcom.com for reference, 2022-Jan-05