429 RESOURCE_EXHAUSTED despite Tier 1 limits not being reached

Hello,

I am receiving a 429 RESOURCE_EXHAUSTED error when using the Gemini API.

My project is “music” and it is currently Tier 1.

Google AI Studio shows that the displayed rate limits have not been reached:

Gemini 3.6 Flash

  • RPM: 9 / 1,000
  • TPM: 13.59K / 2M
  • RPD: 97 / 10K

However, my application repeatedly fails with:

429 RESOURCE_EXHAUSTED
Resource has been exhausted (e.g. check quota).

The API key is valid, and the project is active.
The error continues even though the displayed RPM, TPM, and RPD limits are well below the quota.

Could you please check whether there is another quota, model-specific restriction, or backend issue causing this error?

Thank you.