You might have to "whitelist" SubSim to get the download to go. or use a different web browser, such as FireFox or Edge. You still might have to "whitelist" SubSim though...
FotRSU v1.8 Download
Recent site updates have changed the links below that, and it might take a bit of finagling to get those also. If you continue to have issues, PM a site moderator or the admin and let them know.