Forum Discussion
Using another UPN to login to Exchange Online
Hi,
On my premise, users are using the UPN to login @mycompany.com , we have another small company called smallcom.com, in my premise, I added an extra UPN for them so they can log in using mailto:alias@smallcom.com as everything is hosted in my datacenter.
I am moving to Office 365, and don't know how to add additional UPN to the user on my tenant as once I add the additional UPN, the login process keeps failing.
Note: I added the smallcom.com as domain and validate it.
so is this a possible scenario
farism Hello, perhaps this preview is applicable in your scenario?
"This feature tells the Azure AD login servers to not only check the sign-in name against UPN values, but also against ProxyAddresses values for the email address."
'Sign-in to Azure Active Directory using email as an alternate login ID (preview)'
https://docs.microsoft.com/en-us/azure/active-directory/authentication/howto-authentication-use-email-signin
7 Replies
There's no such thing as additional/extra UPN in Exchange Online. You should have no problem adding another domain and changing the user's UPN to match said domain though. And if needed you can redirect the sign-in process to on-premises, so that users keep the same login experience.
Thanks for the reply,
I have it already as Domain and I set the user to use this domain for login and I am using AD Connect Pass-through, so I assume all authentication are passing to my local AD. But still users from this domain keep failing to login...
farism Hello, perhaps this preview is applicable in your scenario?
"This feature tells the Azure AD login servers to not only check the sign-in name against UPN values, but also against ProxyAddresses values for the email address."
'Sign-in to Azure Active Directory using email as an alternate login ID (preview)'
https://docs.microsoft.com/en-us/azure/active-directory/authentication/howto-authentication-use-email-signin
