It may be that you have simply made a typing mistake, and there is an error in the name of the remote host computer. In this case you should also receive an error stating that the host is unknown.

Check that you have defined the correct port number for the connection. The port can be changed on the Connection page of the Settings dialog.

There may be problems with the configuration or physical setup of the network connection. Verify that other network connections are functioning.

This problem may also arise if your local system is protected by a firewall and the firewall has not been properly configured. If you suspect that this is the case, ask your local system administrator to reconfigure the firewall.

There may also be a temporary problem with the remote host computer. If this is the case, you should wait for a while and try to connect again later. Contact the administrator of the remote host computer for additional information.