Hello @Lucía Sánchez,
great to see you are exploring Azure Digital Twins, including the 3D studio visualization.
The step that fails is the dialog which generated a number of twins and relations within your current ADT environment.
I see a similar issue in three different ADT environments:
Perhaps it's a temporary problem (portal-related, not service-related) so try it later again.
I try to reach out to the product team.
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