Forum Discussion
Exchange Hybrid and external email
Hello I enabled a Private group to "allow external senders to email this group" I see it in the GAL. but its failing with a Remote Server returned '550 5.1.1 User Unknown' What do i need to c...
Define "private group"? Generally speaking, you'd want to toggle the -RequireSenderAuthenticationEnabled flag. But the error message above suggests a different issue.
a new group under Outlook client https://support.microsoft.com/en-us/office/create-a-group-in-outlook-04d0c9cf-6864-423c-a380-4fa858f27102
that is set to private and appears as a private group under the exchange admin center.- Got that part, but not sure where on-premises Exchange comes into play in your scenario, as Groups are pure cloud objects? In any case, for a Group to start receiving external messages, you'd want to toggle the RequireSenderAuthenticationEnabled flag.
- Had to create New-MailContact on premise AD
