When you try to convert an existing domain from standard authentication to federated authentication in Microsoft SharePoint Online by using the Convert-MSOLDomaintoFederated cmdlet, you receive the following error message:
PS C:\Windows\system32> Convert-MsolDomainToFederated -DomainName <domain.contoso.com>
Convert-MsolDomainToFederated :
Microsoft.Online.Administration.Automation.IdentityInternalServiceException
At line:1 char:30
+ Convert-MsolDomainToFederated <<<< -DomainName <domain.contoso.com>
+ CategoryInfo : NotSpecified: (:) [Convert-MsolDomainToFederated],
FederationException + FullyQualifiedErrorId :
Microsoft.Online.Administration.Automation.IdentityInternalServiceException,
Microsoft.Online.Identity.Federation.Powershell.ConvertDomainToFederated
PS C:\Windows\system32> Convert-MsolDomainToFederated -DomainName <domain.contoso.com>
Convert-MsolDomainToFederated :
Microsoft.Online.Administration.Automation.IdentityInternalServiceException
At line:1 char:30
+ Convert-MsolDomainToFederated <<<< -DomainName <domain.contoso.com>
+ CategoryInfo : NotSpecified: (:) [Convert-MsolDomainToFederated],
FederationException + FullyQualifiedErrorId :
Microsoft.Online.Administration.Automation.IdentityInternalServiceException,
Microsoft.Online.Identity.Federation.Powershell.ConvertDomainToFederated