When working with the Box APIs, you may receive the following response:
{"error":"unauthorized_client","error_description":"The grant type is unauthorized for this client_id"}
You will receive the error above if you try to obtain a token via standard OAuth2, but have selected Server Auth as your authentication method.
Resolution Steps
To resolve this error, you will need to change the authentication method for your application to standard OAuth2, in the configuration tab of the developer console, or obtain a token via the server auth method instead.
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