configure apache reverse proxy with non-standard port for SSL connection (e.g. 8443 instead of 443)

In the ssl.conf file (the config snippet produced by artifactory), change:
    RewriteCond "%{HTTP_HOST}" "^(.*)\.<jfrog_url>$"
to:
    RewriteCond "%{HTTP_HOST}" "^(.*)\.<jfrog_url>(:\d+)?$"

Then, restart the apache server for the changes to take place.