The Office 365 admin panel is limited in only allowing the admin to add a single email address to a mail contact. If you want to add multiple addresses, you have to use PowerShell. Use the following set of commands to add and verify the additional proxy addresses.
- To connect powershell to Office 365, open Powershell
- Type the following command: $Cred = Get-Credential
- Enter the username / password of a valid O365 admin account
- Type the following command: $Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://ps.outlook.com/powershell/ -Credential $Cred -Authentication Basic –AllowRedirection
- Type the following command: Import-PSSession $Session
- Powershell is now attached to Office 365 Exchange and we can run the command to add addresses to the mail contact. Note that the primary address should have uppercase “SMTP:” prepended (there can be only one uppercase entry for the primary address. Additional secondary addresses must have lowercase otherwise there will be mail flow problems.)
- Set-MailContact “User Name” -EmailAddresses “SMTP:firstname.lastname@example.org”,”smtp:email@example.com”
To confirm this has worked run the following command:
- Get-MailContact “User Name” | select -ExpandProperty EmailAddresses
- Check the admin web interface and check the external email address is correct. This is the address receiving all incoming email for the contact.