Kaltura_Client_Exception thrown

Invalid KS "MWZiNTlhZWQ2YWFlYTA3NmJhN2EyMDRhOWI2YzA2OTAwYjZlNmNhY3wxMDE7OzE0NzUwNzE4MzE7MjsxNDc0OTg1NDMxLjgxMjY7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"