AQ API key returns 401 ACCESS_TOKEN_TYPE_UNSUPPORTED on Gemini 3.6 Flash

Gemini API
1

I am getting a persistent 401 ACCESS_TOKEN_TYPE_UNSUPPORTED
when calling the Gemini Developer API with a newly generated AQ
authorization key.

Project: Growith
Model: gemini-3.6-flash
API: Generative Language API

The following has been verified:

  • Generative Language API is enabled.
  • The API key is active.
  • The old API key was deleted.
  • A brand-new AQ key was generated.
  • The new AQ key was copied directly into my local .env.
  • The server was fully restarted.
  • The request uses the documented Gemini API endpoint.
  • The API key is passed using the ?key= query parameter.
  • The same 401 occurs with the newly generated key.
  • Error: ACCESS_TOKEN_TYPE_UNSUPPORTED
  • HTTP 401 UNAUTHENTICATED

The same error persists after key rotation.

Could you confirm whether there is currently an issue with
AQ authorization key provisioning/authentication for the
Generative Language API?

2

Hi @youngsik_Yoon, This error usually occurs when the provided API key is invalid, truncated, or unlinked and has nothing to do with AQ type keys. The AQ key format is fully supported by the Gemini API, official SDKs, and REST endpoints.

Try generating a new API key for your project in Google AI Studio. Pass the key using the GEMINI_API_KEY environment variable or the x-goog-api-key header. If you still face issues, please share a CURL request with us.