Tthe package service is installed on the SMP. It seemed to be running correctly but it was not publishing https codebases. The respective HTTPS codebases settings have been enable as per the following article:
"Package Server is not publishing HTTPS codebases" -- KB 172128
ITMS 8.x
When running SMP and Site Server on the same host you can/t override the certificate used on the Site Server. This issue is that you'd have two web servers binding to port 443 using two different certificates. This is why it failed.