SUMMARY
Brand-new Cloud org, billing account, and projects created today (2026-08-04). Every generateContent call fails with 429 “prepayment credits are depleted,” despite the projects being Tier 1 Postpay with an active linked Cloud billing account. We have never used Prepay and have never purchased credits, so there is no balance that could be depleted. This looks like the known backend bug that switches Postpay accounts to Prepay.
DETAILS
Organization: provider-management-org (6549213127..)
Billing account: 01D228-B52ED3-964A.. (Postpay, active, valid card)
Affected projects: vocacast-prod (project number 7846705391..)
vocacast-dev (project number 10366299345..)
Both projects show “Tier 1 · Postpay” in AI Studio.
Cloud reports billing correctly linked on both:
$ gcloud billing projects describe vocacast-prod
billingAccountName: billingAccounts/01D228-B52ED3-964A..
billingEnabled: true
ERROR
Request:
POST https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash-lite:generateContent?key=
Response:
{
“error”: {
“code”: 429,
“status”: “RESOURCE_EXHAUSTED”,
“message”: “Your prepayment credits are depleted. Please go to AI Studio at [link] to manage your project and billing.”
}
}
Reproduces on gemini-2.5-flash-lite and gemini-3-flash-preview.
USEFUL DIAGNOSTIC
GET /v1beta/models → 200, returns 50 models
POST …/generateContent → 429 “prepayment credits are depleted”
So the key authenticates and the project is visible; only billed generation is rejected. That points at billing state rather than key or project config.
TIMELINE (UTC, 2026-08-04)
~09:50 org, billing account, and both projects created
~10:00 Generative Language API enabled on both projects
10:10 API keys created via gcloud, restricted to generativelanguage.googleapis. com
10:23 first generateContent calls → 429, continuously since
10:28 AI Studio shows “Tier 1 · Postpay” for both projects while the API continues to return the prepay error
ALREADY TRIED (no effect)
- Fresh API keys on both projects (created today; not a stale-key issue)
- Verified billing linkage via gcloud (billingEnabled: true, correct account)
- Confirmed Tier 1 in AI Studio rate-limit page for both projects
- Waited and retried over ~30 minutes
REQUEST
Please perform a manual billing sync and revert the erroneous Prepay switch on billing account 01D228-B52ED3-964A.. and projects 7846705391.. and 10366299345.., so that Postpay billing is honored.
We do not want to switch to Prepay, since that change is irreversible and would stop all projects on the billing account at zero balance.
This is blocking a production workload; we have temporarily failed over to a different LLM provider and would like to move back.