For what you are saying I guess that if you run a /etc/init.d/hostd status services should be running... Doble check please.
Maybe its a networking issue. Are you connected in the same L2 as the management interfaces of the esxi/vcenter or in a routed network?
Try this please:
Telnet the ESXi that is not working from your terminal.
- telnet ESXIIP 443
SSH into vCenter and:
curl -v telnet://ESXIIP:443
Double check DG and Netmask configuration on the ESXi that is not working
Cheers
