Gemini API 404 NOT_FOUND Error with High Input Tokens — Fix Guide

What this error means

google.genai.errors.ClientError: 404 NOT_FOUND — Requested entity was not found is a Gemini API failure pattern reported for developers trying to fix gemini image models returning 404 not_found when input token count exceeds ~15k tokens. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

Active GitHub issue (2026-05-08) reports 404 NOT_FOUND error for Gemini image models with high input tokens. The error message is misleading (entity not found vs. token limit exceeded), making this a high-value troubleshooting target.

Common causes

• Gemini 3 image models (gemini-3.1-flash-image-preview, gemini-3-pro-image-preview) return a misleading 404 NOT_FOUND error when the input token count exceeds ~15k — well below the documented model card maximums. Developers are confused by the 404 error when the model actually exists; the real issue is a server-side token limit.
• Active GitHub issue (2026-05-08) reports 404 NOT_FOUND error for Gemini image models with high input tokens. The error message is misleading (entity not found vs. token limit exceeded), making this a high-value troubleshooting target.

Quick fixes

1. Confirm the exact error signature matches google.genai.errors.ClientError: 404 NOT_FOUND — Requested entity was not found.
2. Check the Gemini API account, local tool state, and provider configuration involved in the failing workflow.
3. Compare the failing environment with a known working setup, then change one configuration value at a time.

Platform/tool-specific checks

• Verify the command, editor, extension, or API client that produced the error.
• Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
• Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

1. Capture the exact error message and the command, editor action, or request that triggered it.
2. Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
3. Review the source evidence below and compare it with your environment.
4. Apply one change at a time and rerun the smallest failing action.
5. Keep the working fix documented for the team or deployment environment.

How to prevent it

• Keep provider/tool configuration documented.
• Record non-secret diagnostics such as tool version, provider name, model name, and command path.
• Add a lightweight check before CI or production workflows depend on the tool.

Sources checked

• https://github.com/googleapis/python-genai/issues/2397

Evidence note: Active GitHub issue (2026-05-08) reports 404 NOT_FOUND error for Gemini image models with high input tokens. The error message is misleading (entity not found vs. token limit exceeded), making this a high-value troubleshooting target.

Related errors

• Gemini API token limit exceeded
• Gemini image model context length error

FAQ

What should I check first?

Start with the exact google.genai.errors.ClientError: 404 NOT_FOUND — Requested entity was not found text and the smallest action that reproduces it.

Can I ignore this error?

No. Treat it as a failed Gemini API workflow until the root cause is understood.

Is this guaranteed to have one fix?

No. The imported evidence supports the troubleshooting path above, but tool behavior can vary by account, plan, version, provider, and local configuration.

How do I know the fix worked?

Rerun the same command, editor action, or request. The fix is working when that action completes without google.genai.errors.ClientError: 404 NOT_FOUND — Requested entity was not found.