If you are on a PC that has connected before from the same location, to the same host system, the problem is almost certainly outside of Anzio. The server (host system) you're trying to connect to may be down. A new firewall may have been installed, either on your PC or at the host end.
If several PCs in your office stop connecting to the same host system, it is even more likely that the problem is on the server. See above.
If you are trying to connect to your own office from home for the first time, and nobody else has done that before (from outside the office), the office may not be configured right. Many things need to be in place at the office for that to be possible and secure. Your best bet is to use a local network consultant.
If you don't know who runs the system you're trying to connect to, we don't either, and we can't help you with that.