If you have added any domain on HUB server and you are not able to see this domain on Edge server then might be your synchronization between your hub and edge servers are not working. To test this you can run following command;
If the connection result is showing failed then you need to do edge subscription again for this edge server. Following are the steps for this
1. On the edge server which is not synchronizing run following command;
New-EdgeSubscription -filename "C:\temp\edgesub.xml"
now copy this .xml file to hub server and run following command
New-EdgeSubscription -filename "C:\temp\edgesub.xml" –site London
Please note the site parameter is required to bind this edge server to a specific AD site.
Now run following command
You will notice that now the edge server is synchronizing data with HUB server.
For verification you can run test command again and this time it should show you the success message