How to add subdomains to Office 365 (2015 Edition)
Written on December 14, 2015

If you’ve found this post, you’ve probably tried to add a subdomain to Office 365 and run across this error: is a subdomain of a domain that was added by using the Microsoft Online Services Module for Windows PowerShell so you’ll need to also use Windows PowerShell to add to Microsoft Online Services.

or similar.

The following commands should be used from the Windows Azure Active Directory PowerShell Module to resolve this:

For a federated domain (AD FS)

New-MsolDomain -Name -Authentication Federated

For a managed (standard, in cloud, non-federated, password sync, cloud only, whatever you’d like to call it) domain

New-MsolDomain -Name -Authentication Managed

You can use Get-MsolDomain to validate this configuration.

Keep in mind that subdomains must use the same authentication method as any parent domains.

Cmdlets used in this post:


There's no commenting functionality here. If you'd like to comment, please either mention me (@[email protected]) on Mastodon or email me. I don't have any logging or analytics running on this website, so if you found something useful or interesting it would mean a lot to hear from you.