If you receive an "invalid secret key" error while attempting to access the KCET portal, it typically means that the key you are using is incorrect or has expired. To resolve this issue, ensure that you are entering the correct secret key provided to you during the registration or application process. Double-check for any typographical errors, and if necessary, try regenerating or requesting a new secret key through the KCET website or by contacting their support team for assistance.