Kaltura_Client_Exception thrown

Invalid KS "MTFlM2VmYTJiYTIyMGIxMWY3NjY1ZTJjODgzZWE1ZGQ4ZmJlMmVmYXwxMDE7OzE0ODgwMTI1Njc7MjsxNDg3OTI2MTY3LjY0NTU7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"