Hello Nijel,
When I was using the cloud address book I needed to repeatedly sign back in to the server because it would sign me out very frequently and this made adding and removing clients very tedious or impossible.
This might be caused by intermittent network connectivity or network configuration problems. You may not notice that when web surfing, for example, because a web browser briefly connects to a web server, downloads the page, and then disconnects. With remote access software though you need a long lasting connectivity and sometimes network problems may affect how your remote connection works.
As a side note, I can only connect and see the online status of clients when I am on the same LAN as the server if my Viewer PC's network connection is routed through a VPN.
For some reason it doesn't work from inside the network. When I'm using my cellular hotspot or another ISP or my VPN it works but I can't connect to the server domain address from inside the network.
This has something to do with your specific network configuration. Unfortunately, with so many possible factors we cannot tell for sure why this is happening. Still, you should be able to communicate with your server directly on the same LAN using its hostname or domain address, it is very strange that you cannot.
A side note to the side note; the only way I am able to make clients I know are online appear online and connectable while my Viewer is on the same LAN as the server without using a VPN is if I edit the server address on each client on the Viewer address book and remove the domain name of the server and enter the server LAN IP address. Obviously this isn't going to work for when I'm on the road so I just use my VPN in the office instead.
Here is a question - why would you want to use the server (the
relay role, that is, to broker a remote connection) if you have direct connectivity with remote machines, such as through VPN? You could simply connect from Viewer to Host using the Host's VPN address, you don't need to use the server for that.
Please, note that server's roles may work independently. For instance, you can sync your address book through the server and still connect directly to remote machines.