The underlying connection was closed
OR
The operation has timed-out
OR
Unable to connect to the remote server

Some web hosts (such 1and1 Internet) use proxy servers inside their network.  If you encounter any connectivity issues (when PDshop makes outside web requests) than your web host may have failed to configure the server's master .config files.  So, you may need to modify your own web.config to work around their proxy servers.  

For example, you may need to add default proxy settings to your web.config:

1and1 Examples:

<system.net>
<defaultProxy>
<proxy usesystemdefault="False" bypassonlocal="False" proxyaddress="http://ntproxy.1and1.com:3128" />
</defaultProxy>
</system.net>

-OR-

<system.net>
<defaultProxy>
<proxy usesystemdefault="False" proxyaddress="http://ntproxy.schlund.de:3128" bypassonlocal="False" />
</defaultProxy>
</system.net>

--OR--

<system.net>
<defaultProxy>
<proxy usesystemdefault = "false" bypassonlocal="false" proxyaddress="ntproxyus.lxa.perfora.net:3128" />
</defaultProxy>
</system.net>


NOTE: Contact your web host before making these changes, these are just examples, the actual proxy settings for your server may differ.

Typically you add proxy settings just after the system.web section, but before the appsettings section.

Article Applies to: ASP.NET (Microsoft's .NET), PDshop .NET