Primary Issue Description: Need to add email accounts for second domain, but cannot choose second domain when adding new User
Subscription type and # of Licenses: EXCHANGE ONLINE (PLAN 1)- 3
Problem Description (Scope): Need to add email accounts for second domain, but cannot choose second domain when adding new User
Repro Steps: if able to reproduce
Specific Error Message
The proxy address”SMTP:firstname.lastname@example.org” is already being used by the proxy addresses or LegacyExchangeDN. Please choose another proxy address.
This can be resolved using Powershell:
In order to achieve this, you need to create the shared mailbox with a different alias and then change the UPN manually once it is created in Powershell.
PS New-Mailbox -Name “Info Shared Mailbox 2” -Alias info2 -Shared -PrimarySMTPAddress Info2@contoso.com
You can now see the mailbox and the UPN it has been assigned.
PS Get-mailbox info2 | select userprincipalname
Set the correct login name With the Set-Mailbox command like this:
PS Set-mailbox info2 -MicrosoftOnlineServicesID email@example.com
Verify the correct UPN (firstname.lastname@example.org)
PS get-mailbox info2 | select userprincipalname