Kaltura_Client_Exception thrown

Invalid KS "MmFmYzFjNWEyMjE1YjRjNjEwMTM5YjY5MmQ2YTc3OTEyOGU5ZGQ4NHwxMDE7OzE0NzU0MzA2MDk7MjsxNDc1MzQ0MjA5LjA1MDQ7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"