Unable to connect to Plesk Control Panel

[smiller]

Parallels Plesk Panel 9.2.3 for Microsoft Windows
Operating System : Windows Server 2003 Enterprise Edition Service Pack 2

I can no longer connect to plesk control remotely using https://xxx.xx.xxx.xxx:8443/
If I log on to the server using a remote desktop connection and use https://localhost:8443 it works fine.

Using Google Chrome the error message returned is:-

The connection to xxx.xx.xxx.xxx was interrupted.

Error 101 (net::ERR_CONNECTION_RESET): The connection was reset.

Please could someone help, it would be much appreciated.