All the SQL Server connections are showing the error,
"Cannot connect to SQL Server instance '<SERVERNAME>' : Exception has been thrown by the target of an invocation."
The Windows Event Log Viewer will show this error,
"Windows cannot determine the user or computer name. (The specified user does not exist. ). Group Policy processing aborted."
Please review the following Microsoft link for a possible DNS corruption and search for search for Event ID 1053.
http://support.microsoft.com/kb/329708 and http://www.chicagotech.net/wineventid.htm
