When configuring a SQL 2008 SP1 reporting server I got this error, “The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel” when I trying to view the http://servername/Reports url. This appeared a bit odd as I wasn’t trying to connect via SSL to the site.
Luckily the fix here was an easy one, I simply had to alter the “rsreportserver.config” file and make the following change.
<Add Key="SecureConnectionLevel" Value="2"/>
<Add Key="SecureConnectionLevel" Value="0"/>
Which resolved the issue and displayed the page.
There is more detail on this here. This basically means that this will need to be revisited again when it comes time to enable reporting services out to the web via an SSL.