access_denied:The resource owner or authorization server denied the request.
credential_flow_not_configured:Resource Owner Password Credentials flow failed due to Doorkeeper.configure.resource_owner_from_credentials being unconfigured.
invalid_client:Client authentication failed due to unknown client, no client authentication included, or unsupported authentication method.
invalid_grant:The provided authorization grant is invalid, expired, revoked, does not match the redirection URI used in the authorization request, or was issued to another client.
invalid_redirect_uri:The redirect uri included is not valid.
invalid_request:The request is missing a required parameter, includes an unsupported parameter value, or is otherwise malformed.
invalid_resource_owner:The provided resource owner credentials are not valid, or resource owner cannot be found
invalid_scope:The requested scope is invalid, unknown, or malformed.
resource_owner_authenticator_not_configured:Resource Owner find failed due to Doorkeeper.configure.resource_owner_authenticator being unconfiged.
server_error:The authorization server encountered an unexpected condition which prevented it from fulfilling the request.
temporarily_unavailable: The authorization server is currently unable to handle the request due to a temporary overloading or maintenance of the server.
unauthorized_client:The client is not authorized to perform this request using this method.
unsupported_grant_type:The authorization grant type is not supported by the authorization server.
unsupported_response_type:The authorization server does not support this response type.