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
Carolyn_Liu
Microsoft
Microsoft1)"550 5.7.64 TenantAttribution; Relay Access Denied": This error is seen for external non microsoft recipients.
Will the error for external microsoft recipients be this: "4.4.62 Mail sent to the wrong Office 365 region"
Can you please confirm?
Answer: yes, see my above reply.
2)Is there a way to tell in which regions the change has gone live so far? example: US, Europe ?
Answer: I may notify in this blog, depend on feasibility, check back often.
3)One more query:
If my accepted domain contains mycompany.com and there is an email arriving with P1 header as 1)"test.mycompany.com" and 2) "abc.test.mycompany.com" (I have used ip address based authentication) , will both mails 1) and 2) get rejected?
Answer: Yes, subdomains are not considered as accepted domains in sender case.