Auth0 Invalid Request Unknown Client Error Occurs During Authorization

An Auth0 authorization request fails with an unknown client error due to a mismatch between the Client ID present in the application code and the actual Client ID residing in the Auth0 Dashboard. Resolving this issue requires verifying and correcting the Client ID in the application configuration. This issue presents when the application attempts to authenticate a user, and Auth0 rejects the request with the following error:

"error": {

               "message": "Unknown client: xxx",*

               "oauthError": "invalid_request",*

               "type": "request-error"*
}

• Auth0
• Applications
• Client ID
• Authorization

The application configuration contains an incorrect Client ID. Typographical errors cause this mismatch during manual entry of the Client ID, such as mistaking a lowercase letter l for the number 1, or an uppercase O for the number 0. Auth0 rejects the authorization request because the submitted Client ID does not exactly match the Client ID residing in the Auth0 Dashboard.

How is the unknown client error resolved?

Navigate to the Auth0 Dashboard to copy the exact Client ID and replace the incorrect value in the application source code.

1. Navigate to the Auth0 Dashboard.
2. Go to Applications and select Applications.
3. Select the affected application.
4. Locate the Client ID field in the Settings tab.
5. Copy the exact Client ID value.
6. Open the application source code or environment configuration file.
7. Replace the incorrect Client ID with the copied value.
8. Save the configuration and initiate a new authorization request to verify the resolution.