This is the second time that the v-sites on a server are not accessible. I can access the server via the UI and I can access the server via ssh, but I cannot access the v-sites. It is only one server, the v-sites on the other servers are fine.

What can I check to see what is happening? I would like to correct this as this particular server is our main business server and if it is down, then we are scr*wed.