I have Enable Keep-Alive enabled in the Apache Webserver global configuration however when testing an specific website set-up using virtualmin the page speed test is advising that we should enable Keep-Alive for the domain, as well as Enable Keep-Alive enabled in the Apache Webserver global configuration do we also need to do this on the virtual host for each domain?
If you have enabled keep-alive in the Apache config file it will be enabled for every domain that uses the server. So something must be wrong in the settings of your website. What you could is editing the .htaccess file of the specific website and add the following code:
Header set Connection keep-alive
This will enable keepalive for that particular domain. You could also re-check your server settings. Is the KeepAlive setting set to “on”?