Skip to content

Unsupported Grant Type

URI: https://docs.ankatech.co/errors/unsupported_grant_type
HTTP Status: 400 Bad Request

This error also corresponds to the RFC 6749 OAuth 2.0 error code unsupported_grant_type of the same name. The RFC 7807 type suffix uses the identical underscore form so the two identifiers match.

When you see this

The token endpoint does not support the grant_type specified in the request.

Common Causes

  • Requesting a grant type the authorization server does not implement.
  • A typo in the grant_type value.
  • Using a deprecated or disabled grant flow.

Response Example

{
  "type": "https://docs.ankatech.co/errors/unsupported_grant_type",
  "title": "Unsupported Grant Type",
  "status": 400,
  "detail": "The grant type 'implicit' is not supported by this authorization server.",
  "instance": "/oauth/token",
  "correlationId": "550e8400-e29b-41d4-a716-446655440000",
  "timestamp": 1730000000
}

Content-Type: application/problem+json — the response follows RFC 7807 Problem Details.

How to Resolve

  1. Use a supported grant type (for example password, client_credentials, or refresh_token).
  2. Check the grant_type spelling and value against the Developer Hub Reference.
  3. Re-submit with a supported grant type.

For full schema definitions, examples, and interactive testing, see the Developer Hub Reference.