Sorry it took me a while to post back. I had to get some other work done and this project was put on hold for a couple of days.
In answer to your question no I did not. I installed the cert using the ISPCONFIG control panel for the website knotpc.com.
Would I simply need to rename then copy the www.knotpc.com
SSL cert.key to the ISPCONFIG /httpd/conf/ssl.key to fix the issue?
Thanks for your ideas on this. Not sure why the ssl for port 81 does not work.