Kaltura_Client_Exception thrown

Invalid KS "MTMwN2U3YzU2ZWRkYzVhYzJjMDUyNDYwMjI5NThmYWQxY2U0Zjc2ZXwxMDE7OzE0OTYyMjQ5ODY7MjsxNDk2MTM4NTg2LjE1NDc7QW5vbnltb3VzO2VkaXQ6Kg==", Error "-1,INVALID_STR"