Azure Active Directory, Change default username to custom domain

New Contributor

Hope everyone is safe and well.

We have synced the local active directory to azure by azure ad connect. All usernames in azure active directory is with the initial default domain name,
Now I want to replace/change all the username to 
Can anyone please advise how can I do that. Just to let you know, I have already verified the custom domain and made it primary domain.

2 Replies
best response confirmed by Eleus_Apon (New Contributor)



Hi, this is most likely happening because your User Principal Names in your on-premises AD are set to username@domain.local instead of your custom email domain.  


If this is the case, what you will need to do it add your custom domain in as an additional UPN suffix in Active Directory domains and trusts, and then change your users UPN's in AD Users and Computers.


Once this is done, AD sync will set the correct UPN in O365.  Try this for one or two of your users first to test it out I would say.


Hope this helps.

I do apologize for replying late. Sorry I was so busy with the migration activity.

Thank you so much for your feedback.