Cannot install Update Manager Extension

[ddawson20111014]

I've recently purchased vSphere Essentials Standard, installed vCenter and Update Manager but when I open the vSphere Client I don't see the Update Manager tab. I finally realized that the plug-in wasn't installed. I went to Plug-ins and saw that it was listed under Available Plug-ins. I clicked to Download and Install but I'm getting an error:

Error

An internal error occurred in the vSphere Client.

Details: Unable to connect to the remote server

Contact VMware support if necessary

Report Error to VMware...

I've tried this using the vSphere client on the vCenter server, and two more machines. I've confirmed that the ESX hosts have the proper (local) DNS servers listed. I'm not sure where to go now. Any help would be very appreciated.

Environment: 2 ESX hosts - one at 3.5 and one new one at 4.1 both with VMs on local/DAS drives.

[AndreTheGiant]

Could be a firewall problem, the VUM Server part that is not working or maybe a simple DNS problem.

First try to connect with RDP to your  vCenter Server and try VUM from localhost.

If it works and you are sure that is not firewall problem, than check DNS resolution.

Andre

[GaneshNetworks]

Looks like a problem described here - http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=101267....

Have a look.

Thanks,

Ganesh

[ddawson20111014]

Grrr. Uninstalled and re-installed on non-custom ports and it's working fine. Need to go back and see what was on those original ports but it's fine now. Thanks for all the replies. They were helpful in doing the basic troubleshooting.