can't connect any more

I have been using PLEX MS for more than a year. Installed on a Synology NAS. Without problems I must say.
Yesterday I installed a secondary NAS at a remote location. I tried to install and access the server, without success. Ever since I can access my main server - I tried all possible combinations of Preferences.xml without any result. I keep getting stuck in the web app at "Looking for servers.." at both Synology NAS networks, locally and remotely - providing the same result.