403 PERMISSION_DENIED "project denied access" on new project — billing + API enable verified, error not in troubleshooting docs

Gemini API
1

Billing tier shown in AI Studio: “Unavailable · Postpay”

Every generateContent call returns 403 PERMISSION_DENIED with message

“Your project has been denied access. Please contact support.”

This error message does not appear in the troubleshooting docs

(https://ai.google.dev/gemini-api/docs/troubleshooting).

The only documented 403 has different wording.

Symptoms apply to ALL models including baseline gemini-2.5-flash,

not just newer 3.5-flash.

Already verified / ruled out:

  • API key auth is valid: GET /v1beta/openai/models returns 200 with 53 models

  • Generative Language API is enabled in Cloud Console for project gen-lang-client-xxx

  • Billing account active with €10 credit, paid postpay configured (Mastercard)

  • “Setup complete” confirmed billing-to-project linkage yesterday

  • Region: Germany — fully supported per docs, no model-specific restriction

  • No API restrictions configured on the key

  • Project has zero usage history, no ToS pattern to flag

Project tier appears stuck in “Unavailable” state. Billing support

confirmed this is outside their scope and recommended filing here.

advise what account-level flag needs clearing.

2

Sorry to hear about this. We’re treating this as a potential bug in Gemini API. Could you please enter the details of projects receiving unexpected 403 errors into this form?