Please follow below steps in order to fix such issue.
1= If you have multiple machines in the HC cluster then same HC build version
must have applied on all HC machines.
2= Network card which holding the hc panel ip address must have High prorirty
(This case only applies incase dual network card in the machine)
To set priority of the network card
Go to start :: run :: Control Panel :: Network Card :: Advanced tab :: Advanced Setting
>>> Bring nic card on top list to set high priority.
3= If firewall is configured between servers then these ports must open for incoming/outgoing ( Tcp/Ip ) request on both machines Sql port
= 1433 HC Server port
= 8788 HC Remoting port
4= Go to Services Management Console by clicking Start-->Run-->services.msc
(Press Enter) and restart the HC Remoting service do this on HC db and problem machine.
5= Incase IIS installed on the machine then recycle HCAppPool from Start > run > inetmgr
> IIS > Application Pool ( this will refresh all hc panel web related services )
6= Follow this last step only incase you have changed the Server ip address
Server starts showing DOWN if you change the ip of your server, as this effect communication between server and hc database server.
In order to resolve this issue consult with kb http://support.hostingc...ction=kb&article=276