User Management API - with Buisnes ID's Domain error

Hi All

I am hoping someone can help I am trying to run the below uri to update a users details.

https://usermanagement.adobe.io/v2/usermanagement/action/{orgId}

I am getting the below response

errormessage : Changes to users are only allowed in claimed domains.
errorCode : error.domain.trust.nonexistent

We have a Buisness ID setup.

I have tried going into the admin console and going to the settings -> identity -> directory - selecting the buisness directory but there is no add domain option.

Is it not possible to update users through the usermangement api with a buisness id setup?

Many Thanks

James