This issue may occur if the vCenter Server IP address (in the vCenter Server agent configuration file on the ESX) is incorrectly set to the loopback IP address 127.0.0.1.
To verify this, open /etc/opt/vmware/vpxa/vpxa.cfg on the ESX 4.0 host and check if the <serverIp> entry contains 127.0.0.1. If it does, you must change the IP address.
To change the IP address in vCenter Server:
- Click Administration > vCenter Server Settings.
- Click Runtime Settings.
- Enter the IP address of the vCenter Server in the vCenter Server Managed IP field under the Managed IP Address heading.
- Click OK.
Note: If you are using NAT between the vCenter Server system and ESX hosts, see Using NAT between the vCenter Server system and ESX hosts (1010652). Ensure that the NAT device is configured to redirect UDP traffic on port 902 to the vCenter Server. Ensure that the vCenter Server Managed IP address is set to the IP address of the external address of the NAT device.
- Close the vSphere Client session connected to vCenter.
- Open a new vSphere Client session with vCenter.
- Connect the ESX host.