Create two addresses with the same prefix through PowerShell and Exchange Online

Question

Hello,

I'm trying to create two addresses with the same prefix but different domains. Example:

******@domain1.com

******@domain2.com

I've done it successfully in the actual Exchange Online site for a tenant, where the emails in question are like that but the aliases for each address look like this (Automatically generated by the EXO site):

******@tenant.onmicrosoft.com

******@tenant.onmicrosoft.com

My question is if this is possible with the New-Mailbox command in PowerShell through the Exchange Online module and avoid the "A user with this name already exists. Use a different name" error in the console.

Thanks.

Answer 1

Hi @ rektbyazure,

Yes. You can use PowerShell to create mailboxes with the same prefix but different domains.

However, when you create a mailbox with another domain name, it is not directly set as the primary SMTP address. Instead, the user principal name consists of Alias and the default domain.

You can check it with the following command:

 Get-Mailbox "user | domain2" | select Name,Alias,UserPrincipalName

Therefore, when you use PowerShell to create the second mailbox, you need to set the alias to be different from the previous mailbox, and then change its email address and alias.

For detailed steps, you can refer to this link:

Create shared mailbox with same alias - ALI TAJRAN

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