# E21033 — SIPTrunkAPIKeyNotEligible

This API key cannot authenticate the trunk, so it cannot be allowed on it.

- **HTTP status**: `422`
- **Type**: `validation_error`
- **Name**: `SIPTrunkAPIKeyNotEligible`

## What to do

A key needs the voice permission at write level, and must not have expired, to authenticate a trunk over SIP Digest. Add the permission to the key you want to use, or choose one that still has it, then set the allowed keys again. Adding the permission is enough on its own, and the key keeps the secret your systems are already configured with.

## Related

- [E21xxx — Voice & SIP trunking](/docs/api/errors/E21xxx): every code in this range
- [Errors](/docs/api/errors): the full wire contract, status mapping, and error catalog
- [Error handling](/docs/guides/errors): branching on `type` and `code`, validation details, and `vendor_code`

## Related resources

- [Should I use a Bird SDK or call the API directly?](/explained/platform/should-i-use-an-sdk-or-call-the-api-directly) (answer)
- [Build your first integration](/learn/paths/integration) (course)
- [Send your first email](/docs/get-started/send-your-first-email) (docs)

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