Unable to connect...

[Traveler]

Hello,
Yesterday, I had a working connection to my Vault server. Today, I get the message, "Unable to connect to http://xxx.xxx.xxx.xxx. No server was found at the specified URL. Web Exception: The underlying connection was closed. Unable to connect to the remote server."

On the server, the Vault Admin tool and the Vault client work as expected.
Two things have changed -- I upgraded the firmware on my router, and can't remember if there is a port I need to forward for Vault. I also ran Windows Update this morning on the computer with the Vault server; it didn't look like there were any changes that would affect Vault.

Any ideas on why I can't connect?

Thanks.

Vault 2.0 server is installed on Win2000 sp3, behind a LinkSys router.
Vault 2.0 client is installed on WinXP Pro, not behind the router.