Enterprise Console: managed computer reports 'Could not contact server'

Issue
Enterprise console displays the message:
Could not contact server
against the name of a managed computer, when that computer attempts to update from a Web CID.

Sophos product and version
Enterprise Console 3.1.0

Operating system
Windows 2003

What to do

• Check that credentials are correct and the webpage is accessible from a browser.
• Work through the following steps to define MIME types. You need to do this in order to download the files.
  1. Right-click My Computer, select Manage,
  2. Select Services and Applications|Internet Information Services (IIS) Manager.
  3. Open Web Sites and select the default website.
  4. Select your InterChk web CID, right click and select 'Properties'.
  5. Select the HTTP Headers tab.
  6. Click MIME types|New.
  7. Next to 'Extension:' enter .* (that's a dot followed by an asterisk.)
  8. Next to 'MIME type:' enter Sophos.