That’s because you have cloned the “identity” of your server, by transferring the plex data folder from your old to your new machine.
You must make them individuals again by editing the advanced Plex configuration on one of the machines.
Here is the way for Windows servers: Moving/Cloning Metadata - #4 by OttoKerner
The Mac of course doesn’t have a registry. It stores those preferences in a different way. Here is how to access and change them: https://support.plex.tv/articles/201105343-advanced-hidden-server-settings/
