Tier 1 Postpay project returns 429 "prepayment credits are depleted" on fresh setup

Gemini API
,
1

My freshly upgraded Gemini API project returns 429 RESOURCE_EXHAUSTED on every generateContent call, with the message “Your prepayment credits are depleted,” even though the project is on Tier 1 Postpay with an active linked Cloud billing account.

Setup details:

  • Project number: 684840081..
  • Project ID: gen-lang-client-07533136..
  • Billing: Upgraded from free trial to full Pay-As-You-Go on 2026-06-25
  • AI Studio shows: Tier 1 · Postpay (後払い)
  • API key: Newly created today, never used successfully (AQ.Ab… new format)
  • ¥47,819 free trial credits remaining (valid until 2026-09-24)

What works:

  • API key authenticates fine
  • Project shows correctly in AI Studio as Tier 1 Postpay

What fails:

  • Every generateContent call to gemini-2.5-flash-preview-tts returns:
    {

“error”: {

“code”: 429,

“message”: “Your prepayment credits are depleted. Please go to AI Studio at https://ai.studio/projects to manage your project and billing.”,

“status”: “RESOURCE_EXHAUSTED”

}

}

This appears to be the same billing sync bug reported by several other users recently. Could you please reset the billing state for this project?

Thank you.