Only ever worked once.

[Meredith Matthews 0]

When I first installed Synergy to connect my two win8.1 machines, it worked beautifully. Then, a week later, I had to reboot one, and regardless of how many times I reboot either machine, I can't get it back up and running (... so yes, I've tried turning it on and off again). The host machine shows no errors, but I get a timeout on the client machine. The client machine can see the host machine, it's showing the correct IP and port, but I get an endless stream of "WARNING: failed to connect to server: Timed out"

[Kyunggeun Lee 0]

Have you checked if the service 'Synergy' is online? I had similar problem many times, and most of the time the cause was service not responding. go to your task manager and on service tab, find synergy and try to restart.