Request allowlist access for Gemini TTS preview (gemini-2.5-flash-preview-tts) - 403 permission denied

Gemini API
1

Hello,

I’m consistently getting a 403 permission denied error when trying to use Gemini’s TTS preview models via Google AI Studio’s Generate Speech playground, and I’d like to request allowlist access if that’s what’s blocking me.

Project name: Default Gemini Project

Project ID: gen-lang-client-07213574..

Project number: 640639995..

(Second project, same issue: Gazali / gen-lang-client-0435514333)

Models requested: gemini-2.5-flash-preview-tts, gemini-2.5-pro-preview-tts

Region: Turkey

Use case: Narrating a Turkish-language podcast episode script using AI Studio’s built-in preset voices (Puck/Zephyr in the multi-speaker “Energetic Co-Host” template). Not voice cloning/replication - just standard TTS generation.

What I’ve already verified:

  • Billing account is active, Tier 1, confirmed on Billing, Rate Limit, and API Keys pages
    • Gemini API (generativelanguage.googleapis.com) is enabled on the project (“API Enabled” in Cloud Console)
      • Deleted and regenerated the API key - same error persists
        • Tried with a completely fresh page load and the default unmodified quickstart template - same error
          • Turkey is listed as a supported region in the general Gemini API availability docs
        • Exact error from AI Studio: “Failed to generate content: permission denied. Please try again.”
        • Backend error captured from network logs: google.internal.alkali.applications.makersuite.v1.MakerSuiteService/GenerateContent, code 7 (PERMISSION_DENIED)
      • Google Cloud Billing support confirmed billing/tier is fully healthy and pointed me here, saying preview TTS audio output models require product-level allowlist access managed by the Generative AI team, which isn’t visible/manageable from the Billing console. I also found the “Gemini-TTS Voice Replication Allowlist” Google Form, but it’s now closed to new responses.
    • Could someone add my project(s) to the allowlist for these TTS preview models, or point me to the current correct channel to request this? Thanks in advance.
2

Hi @Mehmet_Sefik_Arvas
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. Verify your Google Account:

  3. Upgrade to a Paid Tier:

    • If verifying your account does not restore access (or if using a model requiring a paid tier), you can unlock access by adding prepayment credits directly in Google AI Studio or attaching a Google Cloud Billing account in the Google Cloud Console.