429 "prepayment credits are depleted" despite confirmed valid balance and correct key/project — manual billing sync request

Project ID: gen-lang-client-06876323..
Billing Account: Cloud Prepay 010F2F-D2D7E8-A863.. (Tier 2, Prepay)
Prepay balance shown in AI Studio: ₩37,320 (confirmed via billing page)

Error on every generateContent call:
429 RESOURCE_EXHAUSTED
“Your prepayment credits are depleted. Please go to AI Studio at
https://ai.studio/projects to manage your project and billing.”

What I’ve already ruled out:

  • API key belongs to this exact project (Default Gemini Project) — confirmed
    by matching the key suffix in the AI Studio API Keys page. Only one key
    exists on this account, so there is no key/project mismatch.
  • Auto-recharge is enabled with a trigger threshold of ₩1,000. It has NOT
    fired, and the balance remains ₩37,320 unchanged. If the prepay ledger
    actually read ₩0, auto-recharge should have triggered immediately. It did
    not, which suggests the billing ledger itself is intact and the ₩0 signal
    is coming from somewhere else (serving layer, not the ledger).
  • models.list() works fine — only generate_content() fails.
  • Tested with two different image-gen code paths (Imagen-based default and
    a generateContent-based fallback) — both fail identically, so this isn’t
    model-specific.
  • Not a rate-limit issue — usage over the relevant period has been minimal
    and this started suddenly, not gradually.

This matches the billing-sync pattern reported in several other recent
threads here (e.g. stale/desynced prepay state after the June 2026 Prepay
billing changes), rather than an actual insufficient-funds condition.

Could someone from the team trigger a manual billing sync for this project?
Happy to provide any additional diagnostic info needed.

Hi

Can you DM me your billing account ID ?

Hello @noyoung ,

Could you please check if you can see the positive balance in https://aistudio.google.com/billing?