How to create Custom Speech service in AI Foundry resource, key-based auth disabled

Question

Hi there,

I am facing issues when trying to create a Custom Speech service in my AI Foundry project. I have Cognitive Services User access on the resource and AI Account Owner on the project, but whenever I try to create a Speech service, I get the below error:

Failed to load finetune custom speech task locales AuthenticationTypeDisabled: Key based authentication is disabled for this resource.
AxiosError: Request failed with status code 403

I have tried following steps from this MSLearn article and enabled Entra ID authentication for the Foundry project via connected resources (connected to the Foundry resource): https://learn.microsoft.com/en-us/azure/ai-foundry/foundry-models/how-to/configure-entra-id.

But I still face the same error. Please let me know how to proceed without enabling Key based authentication for the resource.

Answer 1

Hi Quynh Huynh (NON EA SC ALT) ,

Thanks for sharing the details. From your description, it looks like you’re trying to create or connect a Custom Speech resource inside Azure AI Foundry, and you’re seeing the error.

This issue usually occurs when your Speech resource has key-based authentication disabled, but the AI Foundry workflow (or API call) internally attempts to use key-based authentication for validation. While the Azure portal UI can sometimes handle this automatically, the API and fine-tuning setup path within AI Foundry still require access through keys for certain operations, especially when initializing a Custom Speech project or retrieving locales.

You can replicate the issue by creating a Speech resource with only Azure AD (Entra ID) authentication enabled, then trying to start a Custom Speech fine-tuning project via the AI Foundry interface or REST API. The operation will likely fail with a 403 error when the resource doesn’t support key-based authentication.

Follow some Troubleshooting Steps:

1.Check Authentication Settings:

• Go to your Speech resource in the Azure Portal → Keys and Endpoint → confirm if key-based authentication is disabled.
• Temporarily enable key-based authentication and retry the operation.

2.Verify Region and Access:

• Ensure your Speech resource is in a region that supports Custom Speech fine-tuning.
• Make sure your user or service principal has the required roles: Cognitive Services User on the Speech resource and AI Project Owner in Foundry.

3.Reattach Resource:

• In AI Foundry, disconnect and re-add the Speech resource connection after enabling key-based auth to refresh credentials.

4.Retry Fine-Tuning or Dataset Upload:

• After reattaching, try creating the Custom Speech project again or call the API. The operation should now succeed if key-based auth is available.

Reference Documentation:

• Create a Custom Speech project – Azure AI Speech
• Azure AI Foundry – Connect AI Services I hope this clears things up! Thankyou