Unexpected (403): {"requestId":"d09309fc-4f89-44cb-9e05-b2bec52478ee","errorCode":"FeatureNotAvailab

[poorvi_pj]

Hi Team,

I am trying to create a Microsoft Fabric Ontology (preview) programmatically using Python and the Fabric REST API.

Scenario

• Using Service Principal authentication (Client ID / Secret)
• Building ontology definition dynamically from Lakehouse tables
• Calling:
  POST /v1/workspaces/{workspaceId}/ontologies

Issue

The API call fails with the following error:

403 Forbidden
{
  "requestId": "xxxx",
  "errorCode": "FeatureNotAvailable",
  "message": "The feature is not available"
}

Observations

• GET /ontologies works successfully
• Authentication token is valid
• Workspace and Lakehouse access are correctly configured
• Ontology feature is visible in Fabric UI (preview)

Is Ontology API creation restricted for Service Principals in preview?

Or any guidance would be greatly appreciated.

Thanks!

[arabalca]

Hi @poorvi_pj ,

Were you able to solve the problem?

If this helps solve your problem, I’d appreciate it if you could mark it as the accepted solution and give it a like 👍

Thanks

[arabalca]

Hi @poorvi_pj 

The 403 FeatureNotAvailable when creating an Ontology via Service Principal usually has two causes:

1. Tenant Settings not enabled

The Ontology API requires two settings active in the Admin Portal:

• Enable Ontology item (preview)
• User can create Graph (preview)

The item being visible in the UI doesn't guarantee these are enabled. Also make sure the Service Principal (or its security group) is included in the scope of each setting.

→ Required tenant settings for Ontology

2. The API does support Service Principals

The POST /v1/workspaces/{workspaceId}/ontologies endpoint explicitly supports SP/Managed Identity. What is mandatory: Item.ReadWrite.All scope with admin consent and Contributor role in the workspace (Viewer is enough for GET, but not for POST).

→ Create Ontology - REST API

Additional tip: confirm the workspace is on an F-SKU (Fabric capacity). On Trial or PPU, Ontology may appear visible in preview but fail on API creation.

If this helps solve your problem, I’d appreciate it if you could mark it as the accepted solution and give it a like 👍

Thanks