Hello Adam,
Thank you for your message.
Could you please double-check if you have specified your custom server's address for the auto-imported connections? This can be done in the
Default connection properties menu, in the
Auto-import window:
1. In the Auto-import window click
Default connection properties button.
2. Navigate to the
Connection tab, sel ect
Internet-ID connection and click
Change button.
3. Deselect the
Use default server checkbox and specify your server address exactly as it should be accessible fr om the Viewer side:

For more information please also refer to the highlighted guide
here.
As for the Hosts that are already added to your address book, this can be resolved by specifying the server address for multiple connections on any Viewer that is synchronized with the self-hosted RU Server. In order to do so, please do the following:
1. Select multiple connections in your connection list, then right-click and select
Properties:

2. In the connection properties window navigate to the
Internet-ID tab and click
Change.
3. Deselect the
Use default server checkbox and specify your server address:

This way, all of the selected connections use the self-hosted RU Server.
Hope that helps.