I posted this question last fall, but never got an answer and the thread is now locked. We have about 50 users in AzureAD, but about to bring in a few thousand for Office365. When I bring in the user initiially, it makes the primary username jsmith@contoso.onmicrosoft.com. When the users try to go login(hashes sync every 30 minutes) with their normal domain name of jsmith@contoso.com, they fail like the account is not there until I change the username to the match correct domainname from the drop-down menu of jsmith@contoso.com. Then the users can login fine.
Does anyone know of a way I can change this default to contoso.com, instead of having to manually change it for every user? It seems like I once found a location to change the primary domain name, but it still has no impact. Even a powershell script on changing the default suffix would be helpful at this point.
Thanks,