Kaltura_Client_Exception thrown

Invalid KS "MWZkZWMxZjIwOWY2YmU2YmM0ZDI0ZTYxZWFiOTU2MTU5MTAxMDc2NXwxMDE7OzE0OTg2MDgyODc7MjsxNDk4NTIxODg3LjY4MDQ7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"