Based on the error presented, it appears that the software is having issues connecting to the server. In this case, you can check the IP or host, port, user and password if you use one and then retry the connection attempt. Secondly, if you're using the software on a firewall enabled PC, then you will have to also configure the firewall to allow communication. That error could be caused by this as well.
If you still have issues, start the software, go to Help to read about configuration procedure.