401 Unauthorized Error in Azure OpenAI Deployment (GPT-4o-mini)

Question

We are currently facing authentication issues while deploying GPT-4o-mini on Azure OpenAI. Here are the details of the errors encountered:

1) Issue 1: API Call Failure with 401 Unauthorized

• When making a request to the OpenAI deployment endpoint, we receive the following error: Client error: POST https://it-m7cq0ja0-eastus2.cognitiveservices.azure.com/openai/deployments/gpt-4o-mini/chat/completions?api-version=2024-08-01-preview resulted in a 401 Unauthorized

2) Issue 2: Access Token Issue

We have obtained two API keys for GPT-4o-mini. However, when testing the model, authentication failed: "Unauthorized. Access token is missing, invalid, audience is incorrect (https://cognitiveservices.azure.com), or has expired."

The team is sure that: API keys were correctly copied and used in the Authorization Bearer Token, and endpoint matches our Azure OpenAI deployment region.

Any guidance would be greatly appreciated. Thank you in advance! 🚀

Answer 1

Hi @Bình Đỗ,

We have tested the scenario and were able to make successful API calls without encountering the 401 Unauthorized error. The request returned a 200 OK response, confirming that the API key and endpoint were correctly configured.

To help resolve your issue, please check the following:

1. API Key Usage – Ensure you're passing the key as api-key: <your-api-key> in the header and not using Authorization: Bearer <token>.
2. Correct Endpoint – Verify that your request URL matches the exact format for your Azure OpenAI deployment, including the correct region.
3. Access Control – Confirm that your Azure user has the Azure OpenAI User role assigned in IAM.
4. Regenerate API Key – If the issue persists, try regenerating the API key and testing again.

If you've checked these and are still facing issues, please share the exact error message and request details (excluding sensitive information) so we can assist further.

I hope you understand. Thank you.

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