# API - Error Code 400 or 401

These error codes can have a number of causes.  The response message will indicate the cause of the error.

###

### max\_character\_limit\_exceeded

The maximum number of characters per request depends on the model.

- Flash v2.5 - up to 40,000 characters (\~40 minutes of audio)
- Turbo v2.5 - up to 40,000 characters (\~40 minutes of audio)
- Flash v2 - up to 30,000 characters (\~30 minutes of audio)
- Turbo v2 - up to 30,000 characters (\~30 minutes of audio)
- Multilingual v1 and v2 - up to 10,000 characters (\~10 minutes of audio)
- English v1 and v2 - up to 10,000 characters (\~10 minutes of audio)

###

### invalid\_api\_key

This means that you have not set your API key correctly.  Please make sure you're using "xi-api-key" exactly, with no typos, when setting your API key.

###

### voice\_not\_found

This means that you have entered the incorrect voice\_id.  Please check that you are using the correct voice\_id for the voice you want to use.  You can check this in My Voices.

###

### quota\_exceeded

You have insufficient quota to complete the request.  You can purchase [Pay As You Go credits](/guides/overview-administration-pay-as-you-go), or on legacy Creator, Pro, Scale and Business plans, you can enable [usage based billing](/guides/help-center-8-account-general-what-is-usage-based-billing) from your [Subscription](https://elevenlabs.io/app/subscription) page.

Example 400 response detail:

`"detail": {
 "status": "max_character_limit_exceeded",
 "message": "This request's text has 627 characters and exceeds the character limit of 333 characters for non signed in accounts."
}`

Example 401 response detail:

`"detail": {
 "status": "invalid_api_key",
 "message": "Invalid API key"
}`

## Related pages

- [Administration](./administration-index.md)
- [API reference](./api-reference-index.md)
- [Changelog](./changelog-index.md)
- [ElevenAgents](./elevenagents-index.md)
- [ElevenAPI](./elevenapi-index.md)
- [ElevenCreative](./elevencreative-index.md)
- [ElevenLabs Documentation Docs](../index.md)
- [General Troubleshooting FAQ](./troubleshooting-index.md)
- [General Website FAQ](./website-index.md)
- [Help Center](./help-center-2-index.md)

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