Rhino 4.0 lab license issue

Can anyone tell me what is the cause of this? Most computers in the lab pops up this window.

Restarted computer but still …



There could be several reasons, including:

1.) Your Zoo 4 server is not running.
2.) Access to your Zoo 4 server is blocked by a firewall.
3.) Your Zoo 4 server is on a different network segment, in which case you need to modify your Registry to tell Rhino 4 where to find it.