Update 11/13/2023: We added new information on how to know when this change is released to your organization.
Today, we are announcing an update to our requirements for SMTP relay through Exchange ...
Updated Feb 22, 2024
Version 19.0
Blog Post
Hi Carolyn_Liu The_Exchange_Team
I have a query related to using unique certificate domain configuration during SMTP relay.
Our scenario is similar to this: https://learn.microsoft.com/en-us/exchange/mail-flow-best-practices/use-connectors-to-configure-mail-flow/integrate-office-365-with-an-email-add-on-service
I have created a wild card certificate in the email server with CN=*.emailservice.com
In the Exchange online account i have created an accepted domain as myorg.emailservice.com and created inbound connector with this domain.
But during email relay, email delivery fails with this error: "550 5.7.64 TenantAttribution; Relay Access Denied".
Is this a valid configuration? could you tell what is wrong here?