Manual billing sync request: 429 "prepayment credits are depleted" despite funded Cloud Prepay balance

Gemini API
1

Requesting a manual billing sync. Every generateContent call returns 429
RESOURCE_EXHAUSTED “Your prepayment credits are depleted”, but my Prepay
balance is funded and almost entirely unspent.

Details:

  • Project ID: gen-lang-client-08474747.. (Default Gemini Project)
  • Billing account: Cloud Prepay 0107AD-…-8FE276 (Tier 1)
  • Credit balance: NZ$19.63
  • NZ$20.00 added 28 July 2026; only NZ$0.37 consumed
  • Auto-reload: off

Symptoms:

  • AI Studio Projects page shows a red “No credits” badge for this project,
    despite the positive balance shown on the Billing page
  • Every generateContent request returns 429 RESOURCE_EXHAUSTED with the
    depleted-credits message

Already ruled out:

  • ListModels returns 200 with the same key, so auth and project linkage
    are working
  • Deleted and regenerated the API key; no change
  • Key belongs to this exact project, confirmed on the API keys page
  • Billing account is linked and active

Happy to provide the full billing account ID privately if needed.