Re: Connect-VIServer: The underlying connection was closed: An unexpected error occurred on a send.

LucD,

Thanks for responding. It's W2003 Enterprise SP 2. Not R2. That may be the issue.

This may be part of it as well. I'll try to get the appropriate team to try these steps. From the release notes Known issues:

Connect-VIServer

Connect-VIServer cannot use the Kerberos network authentication protocol to connect to vCenter Server systems that are installed under a custom user account on a Windows system. Connect-VIServer uses NTLM instead.

Workaround: Install and run vCenter Server under the default system account. Alternatively, you can:

1. Add another IP to the Windows system where vCenter Server is running.
2. Register a new A DNS record for the IP.
3. Run the setspn tool to register an SPN for the new DNS record and associate it with the vCenter Server account under which vCenter Server was installed.
   
   For example: To register an SPN for the vc-alias.domain.com DNS and the VCAccount account, run:
   setspn -A -HOST/vc-alias.domain.com Domain\VCAccount
4. Use the new DNS name to connect to the vCenter Server system.
   For example: Run Connect-VIServer vc-alias.domain.com