This failure may be caused by the fact that under the default settings SQL Server does not allow remote connections (Or not...)

I was trying to connect to an SQLServer 2005 instance on one of our machines in the local network and got this error:

TITLE: Connect to Server------------------------------
Cannot connect to Machine\SQLEXPRESS.
------------------------------ADDITIONAL INFORMATION:
An error has occurred while establishing a connection to the server. When connecting to SQL Server 2005, this failure may be caused by the fact that under the default settings SQL Server does not allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified) (Microsoft SQL Server, Error: -1)
For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&EvtSrc=MSSQLServer&EvtID=-1&LinkId=20476
------------------------------BUTTONS:
OK------------------------------

I checked Using "SQL Server Surface Area Configuration" and was amazed to find out that remote connections are enabled:






I've hopelessly restared the SQL service and SQL-Browser service but nothing seemed to help.

Finally in an act of desperation I've disabled the Windows Firewall on the SQLServer machine.
(We don't need it since we have a big firewall protecting the loacl network)

After disabaling the Winows Firewall, everything worked just fine.

The Blogger.