Error when you try to use the New-MSOLDomain command to add a subdomain to an existing domain: New-MsolDomain: Unable to add this domain
Original product version: Cloud Services (Web roles/Worker roles), Azure Active Directory, Microsoft Intune, Azure Backup, Office 365 User and Domain Management, Office 365 Identity Management
Original KB number: 2666578
You try to add a subdomain to an existing domain in a Microsoft cloud service such as Office 365, Microsoft Intune, or Microsoft Azure by using the New-MSOLDomain command. However, you receive the following error message:
New-MsolDomain: Unable to add this domain. It is a subdomain and its authentication type is different from the authentication type of the root domain.
This issue occurs if you try to use the New-MSOLDomain command to add a subdomain to an existing domain that's set up for federated authentication. The New-MSOLDomain command tries to add the subdomain as a standard authentication domain.
To add a subdomain to a domain that's set up for federated authentication, follow these steps:
Connect to Azure Active Directory (Azure AD) by using Windows PowerShell. For more information, see Connect to Azure AD Using Windows PowerShell.
Use the New-MSOLFederatedDomain command.
The syntax to add a subdomain is as follows, where <subdomain> is the name of the subdomain that you want to add:
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