Kaltura_Client_Exception thrown

Invalid KS "MWM5MTMxOGE0NGMyYWQ3M2MxZDY5ODk5NTI2M2Q4MTE2Yzk2NWRmOXwxMDE7OzE0Njk5MDI0MjA7MjsxNDY5ODE2MDIwLjg3Mjg7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"