Free-tier Gemini API returns 403 project denied access across three Flash models

Gemini API
1

Hello Gemini API team,

I need help with a Free Tier Gemini API project. In Google AI Studio, the project is shown as Free Tier and is not marked Restricted. Its rate limits include Gemini 3.8 Flash.

A newly saved Google Gemini credential in n8n 2.41.3 (self-hosted) passes the credential connection test. However, a minimal generateContent request with the prompt “こんにちは” returns HTTP 403: “Your project has been denied access. Please contact support.” I reproduced the same error with gemini-3.8-flash (2026-10-01 00:46 JST), gemini-3.5-flash (01:21 JST), and gemini-3.5-flash-lite (01:23 JST). This appears to affect the project across models.

I want to keep using the Free Tier without enabling billing. The official unexpected-403 reporting form is closed, and the Cloud Billing Support assistant says this account is not a billing administrator. Could the Gemini API team review the project’s access state or advise the appropriate free-tier support route? I can provide the project ID and number privately to an authorized support representative. No API key is included in this post.

2

Hello @JUSToC ,

Getting a 403 API error response and / or seeing “Unavailable” next to your project in AI audio indicates a flag has been placed on your account. To proceed:

If you’re on the free tier with no billing attached, please try the below steps:

  1. Check Model Availability & Rate Limits:

    • Ensure that the model you are requesting is available on your current plan. For example, not all models are available on the free tier. You can verify model availability, quotas, and limits on the AI Studio Rate Limit dashboard.

  2. Ensure you have completed age verification by navigating to Google Account Age Verification and verifying date of birth in Google Account Personal Info.

  3. Once age verification is configured, retry your request or create a new API key in Google AI Studio.

  4. If completing these steps still does not restore access (or if using a model requiring a paid tier), you might want to consider adding prepayment credits directly in Google AI Studio and/ or attaching a Google Cloud Billing account in the Google Cloud Console. Please note this will mean you lose your free tier quota.