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AMZScratchpad

UnsupportedClient (UnauthorizedException): Amazon Creators API error

HTTP 401UnauthorizedExceptionAuthentication (401)Documented by Amazon

What it means

The Credential ID behind the token is not registered for the Creators API.

Message returned by the API: The client identifier is not supported.

Typical causes

  • Credentials from another Login with Amazon application.
  • A deleted Creators API application.

How to fix it

  1. Create the credential under Associates Central → Tools → Creators API.
  2. Use the Credential ID from that CSV, not an ID from the LWA developer console.

Not sure which part fails? Run Test credentials in the Scratchpad. It checks the token, the API access and the partner tag separately.

Example response

{
  "type": "UnauthorizedException",
  "message": "The client identifier is not supported.",
  "reason": "UnsupportedClient"
}

Related errors

  • invalid_client: Amazon’s token endpoint rejected your Credential ID or Secret, so no access token was issued.