thank you for your fast response @fzngagan! I have done the steps in the tutorial (change domainname that discourse points to, rebuild app, and updated my DNS).
When I go to the new IP (of the cloned server), it still will go to the old (live) forum while that IP points to the new (test) forum. (the DNS hasn’t been resolved at this point so I use the ip adress.)
The IP is new so it hasn’t been assigned previously to one of my domains. 