Kaltura_Client_Exception thrown

Invalid KS "MTFhZjM4N2FmMDA5NGE2ZjAyMGFlOTBhMGViMzU2NjE2ODk2NDY2ZXwxMDE7OzE0OTU5ODE4NzE7MjsxNDk1ODk1NDcxLjIwOTg7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"