Kaltura_Client_Exception thrown

Invalid KS "MGM1NWU2MjUxOGU5OTI1NjRhMWJiNmJiZGE0YWY3YjQ3NGQwOGFmYXwxMDE7OzE0NzU0MjQyODQ7MjsxNDc1MzM3ODg0LjE2NTI7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"