If you are receiving that error message then there is likely an issue with the RF signal levels. We will need to confirm what troubleshooting steps you have already attempted.
For this particular issue, please follow all the steps on this article: Troubleshooting Not Authorized Error on Television
If this has all already been attempted and the troubles continue to persist. Please write back here and we'll arrange a private message to be sent to you requesting some account details so we can further assist.
I have tried all the steps referred in the article you referenced.
I have been away for a few months, so both the digital box and the TV have been powered off at the time.
Please let me know what further steps need to be taken.
Private message coming to you now
Retrieving data ...