Kaltura_Client_Exception thrown

Invalid KS "NzNhMTFhMTYyYmFkMWQyMTJjYTY4OWU4YTc1YzU2MWE2NGNiZGUxYnwxMDE7OzE0NzUxMjgwMDQ7MjsxNDc1MDQxNjA0LjU1NjI7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"