The underlying connection was closed: Could not establish trust relationship with remote server

Error Message

When connecting to ArcWeb Services using the toolbar the following error is returned:The underlying connection was closed: Could not establish trust relationship with remote server.

Cause

Internet Explorer 6 is not installed or is corrupted.

Solution or Workaround

1. Navigate to Start > Control Panel > Add/Remove Programs.
2. If the version of Internet Explorer installed is lower than 6 (e.g., version 5), uninstall it.
3. Download and install Internet Explorer 6 from
   Microsoft Windows Update.
   
   

   Note:
   If this does not resolve the problem see method 3 in the related Microsoft knowledge base article.