'Unknown Error', self::RPC_METHOD_NOT_FOUND => 'The request method was not found', self::RPC_INVALID_ARGUMENTS => 'The request method contains one or more invalid arguments', self::INTERNAL_SERVER_ERROR => 'Internal server error', self::SERVER_UNAVAILABLE => 'Server temporarily unavailable', self::INVALID_PUBLIC_KEY => 'The given public key is not valid', self::SESSION_NOT_FOUND => 'The requested session UUID was not found', self::UNSUPPORTED_AUTHENTICATION_TYPE => 'The requested authentication type is not supported by the server' }; } }