A system that is down, or not responding to network requests, has a "Down" icon next to it in the host listing.
To verify that the machine is down, log into another machine in the TeamForge Lab Management environment and use the ping command to see if the machine responds to network traffic. For example, if your machine is cu028.$vars.mgr_domain, the following command should tell you if the machine is reachable:
ping cu028.$vars.mgr_domain
If you are still unable to determine if the system is reachable, or have determined that the system is not reachable, try these steps: