I tried that, but it's still not working.
I installed the SSL cert on the other server in Tools & Settings -> SSL Certificates, it didn't work, then I hit "Make Default" still didn't work, however if I select "Secure Plesk" the Plesk Panel works fine on HTTPS (https://sub.mydomain.com:8443) but...
I have purchased a Wildcard SSL and set sub.mydomain.com to the IP of the other server using DNS records (A record) in plesk.
Everything is installed correctly on the main server, however on the sub.mydomain.com the SSL doesn't work.
Any idea how I can make it work on the other server?
Thanks!