Question : New ESXi 4 Host (not responding) in vCenter

I just installed a new ESXi v4 Host and added it to vCenter.  It was fine for a few minutes, but then dropped saying (not responding).  I right click on it and choose Connect and it connects for a few more minutes before dropping again?  Any ideas why this would happen?  

Answer : New ESXi 4 Host (not responding) in vCenter

Make sure you have an A record in DNS and join it via FQDN.  

Are you adding it to a cluster or standalone?