(The domains already exist in another organization relationship) error when running Hybrid Configuration wizard

Original KB number:   3067526

Symptoms

You want to set up a hybrid deployment between your on-premises Microsoft Exchange Server organization and Exchange Online in Microsoft 365. However, when you run the Hybrid Configuration wizard, the wizard doesn't complete successfully, and you receive a The domains already exist in another organization relationship error message. The full text of this message resembles the following:

ERROR : Subtask Configure execution failed: Configure Organization Relationship Execution of the New-OrganizationRelationship cmdlet has thrown an exception. This may indicate invalid parameters in your hybrid configuration settings.

The domains '<vanitydomain1>', '<vanitydomain2>', '<vanitydomain3>' already exist in another organization relationship. Domains can only exist in one organization relationship. To create an organization relationship with this domain, remove the domain from the other organization relationship.

at Microsoft.Exchange.Management.Hybrid.RemotePowershellSession.RunCommand(String cmdlet, SessionParameters parameters, Boolean ignoreNotFoundErrors)

If you connect to Exchange Online by using remote PowerShell and then run the Get-OrganizationRelationship cmdlet, you receive a message that resembles the following:

Get-OrganizationRelationship
Couldn't find object "<GUID>". Please make sure that it was spelled correctly or specify a different object.
+ CategoryInfo : NotSpecified: (:) [Get-OrganizationRelationship], ManagementObjectNotFoundException
+ FullyQualifiedErrorId : [Server=ServerName,RequestId=RequestId,TimeStamp=TimeStamp] [FailureCategory=Cmdlet-ManagementObjectNotFoundException] EF6F1393,Microsoft.Exchange.Management.SystemConfigurationTasks.GetOrganizationRelationship
+ PSComputerName : outlook.office365.com

Resolution

Contact Microsoft Support, and reference this article.

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