SAP Document AI Trial Basic UI subscription fails

[#1]

Hi Experts,

I am trying to set up SAP Document AI in my SAP BTP Trial account using the "Set Up Account for SAP Document AI" booster.

The booster completes the following steps successfully:

Assigning Service Quotas – Done
Creating Service Instances – Done

However, it fails during:

Subscribing SaaS Applications

Error:

Could not subscribe to:
SAP Document AI Trial Basic UI

When I try to subscribe manually from Instances and Subscriptions, I receive the following error:

You haven't configured your subaccount (for business users) to trust a tenant of SAP Cloud Identity Services using OpenID Connect.
SAML trust isn't supported for this service.
To subscribe this application, use the Establish Trust option to configure trust between your subaccount and SAP Cloud Identity Services.

I would like to know:

Is this expected for newly created SAP BTP Trial accounts?
Do I need to manually establish IAS (OpenID Connect) trust before subscribing to the SAP Document AI Trial Basic UI?
Is this a known issue with the current SAP BTP Trial landscape?
Are there any additional prerequisites required before running the Document AI booster?

Any guidance would be greatly appreciated.

Thank you.

SAP Document AI