# Gemini API HTTP 400 FAILED\_PRECONDITION with multiple API keys

**URL:** <https://discuss.ai.google.dev/t/gemini-api-http-400-failed-precondition-with-multiple-api-keys/190739>\
**Category:** Gemini API\
**Tags:** api\
**Created:** [October 19, 2026, 8:34am UTC](https://discuss.ai.google.dev/t/gemini-api-http-400-failed-precondition-with-multiple-api-keys/190739 "2026-10-19T08:34:53Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![tapferkeit](https://d1dlmcr85iqnpo.cloudfront.net/user_avatar/discuss.ai.google.dev/tapferkeit/32/159723_2.png) [@tapferkeit](https://discuss.ai.google.dev/u/tapferkeit)\
**Post date:** [October 19, 2026, 8:34am UTC](https://discuss.ai.google.dev/t/gemini-api-http-400-failed-precondition-with-multiple-api-keys/190739/1 "2026-10-19T08:34:53Z")

</div>

Hello,

I am experiencing persistent HTTP 400 errors when using the Gemini API.

The API worked successfully until October 9, 2026, but has consistently failed since then.

Environment:

- Google Cloud project: Free Tier
- Model: gemini-3.5-flash-lite
- Gemini API: Enabled
- Authorization API Key: Active
- Bound service account: Active
- Application restrictions: None

Diagnostic results:

1. Interactions API v1  
HTTP 400 / invalid\_request

2. Interactions API v1beta  
HTTP 400 / invalid\_request

3. Models API v1beta  
HTTP 400 / FAILED\_PRECONDITION

4. GenerateContent API v1beta  
HTTP 400 / FAILED\_PRECONDITION

I also created a second Authorization API Key in the same Google Cloud project, bound to a different service account.

Both API keys return HTTP 400 / FAILED\_PRECONDITION when calling the minimal GenerateContent API request.

However, Gemini 3.5 Flash-Lite works successfully in Google AI Studio Playground.

Additional information:

- The project is on the Free Tier.
- Billing is not enabled.
- The Gemini API is enabled.
- Both service accounts are active.
- No application restrictions are configured.
- Rate limits do not appear to be exceeded.

Could someone help identify which project-level or account-level prerequisite might be causing these errors?

Is there a known issue affecting Authorization API Keys or Free Tier projects?

Thank you.