Single Sign on created onmicrosoft.com users. Shouldn't it create users with my mailbox domain?

Question

Starting a new setup this weekend and I have never used single sign on. After researching I figured I was good to go.

My first users should of been johndoe@jaswant .com instead it created johndoe@onmicrosoft.com. I did already have the first 5 users in Microsoft 365 before attempting single sign on. I was hoping it would sync the current users instead of a duplicate username but different domain.

Thoughts?

Thanks

Answer 1

@Jody McLaughlin

Apologies for the delay in answering this query. As I understand your issue is users are synced as johndoe@onmicrosoft.com instead johndoe@jaswant .com.

When you synchronize your on-premises directory with Microsoft 365, you have to have a verified domain in Azure Active Directory (Azure AD). Only the User Principal Names (UPNs) that are associated with the on-premises Active Directory Domain Services (AD DS) domain are synchronized. However, any UPN that contains a non-routable domain, will be synchronized to an .onmicrosoft.com domain.

Would like to understand did you verify your domain in Azure AD/O365 ?

Refer to this article about the steps how to verify the domain - https://learn.microsoft.com/en-us/azure/active-directory/fundamentals/add-custom-domain

Reference: https://learn.microsoft.com/en-us/microsoft-365/enterprise/prepare-a-non-routable-domain-for-directory-synchronization?view=o365-worldwide#:~:text=Save-,Prepare%20a%20non%2Droutable%20domain%20for%20directory%20synchronization,-Article

Let me know if you have any questions.

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