Kaltura_Client_Exception thrown

Invalid KS "MTlkMWYyM2YxM2IyMmM1M2NiMGZkYzEzNjIwNzllY2NmOTJkMGIxMnwxMDE7OzE0NzI3NDYwNTA7MjsxNDcyNjU5NjUwLjEwNzc7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"