iis 6 ssl issues

Hi all,

We recently moved our asp.net to a new box running Windows 2003 SP1 and IIS
6. The site runs over SSL using a self-signed certificate and also uses
client certificates. Users are starting to see intermittent blank pages
and/or the notorious "Page cannot be displayed" message very frequently now.
At that point, if they simply go back and try again it works. This normally
happens on page post postbacks. What could be causing this? The older box
was on the same OS as well and everything worked fine.

TIA!