emscom > emscom Help Desk > Knowledgebase

Search help:

Shared mailbox on secondary domain




Attempting to create a shared mailbox with a similar address to a Universal Principal Name raises a duplicate alias/proxy address error.

PS> New-Mailbox -Shared -Name "Anne Other" -Alias Anne_Other -PrimarySMTPAddress
Windows Live ID "" already exists as a managed Windows Live ID. To use the UseExistingLiveId parameter.


To suppress the error and allow the shared mailbox to be created

1. Create a shared mailbox with a unique alias

PS> New-MailBox -Shared -Name "Anne Other corp" -Alias Anne_Other_Corp -PrimarySMTPAddress

2. Change the WindowsLiveID manually

PS> Set-Mailbox anne_other_corp -MicrosoftOnlineServicesID



Microsoft 365 / Exchange users may require a similar email address on a secondary domain

Eg.  Anne Other works for Contoso and has the primary email address and user principle name (user name)

The initial Microsoft domain was, hence Exchange assigns an implicit alias

The Contoso company launches a new identity, Contoso Corporation with the domain name  Microsoft assume that Anne will be fine using an explicit alias.

However, the explicit alias causes messages to the new domain to be delivered to Anne's original inbox.  This confuses Anne and does not suit the workflow.  Anne would prefer to use a shared mailbox dedicated to the new business identity.




Was this article helpful? yes / no
Related articles Webmail access
Access to company voicemail box
Article details
Article ID: 143
Category: Office 365
Date added: 04-03-2021 08:23:58
Views: 64
Rating (Votes): Article not rated yet (0)

« Go back

Powered by Help Desk Software HESK, in partnership with SysAid Technologies