Hi Guys,

I developed a Payment Tracking System for a client long back using Visual Studio 2005 and SQL Server 2000 which the client used for 1.5+ years. But recently they upgraded their systems and got Windows Vista Ultimate running on them. Now since SQL Server 2000 is not supported on Windows Vista I have to deploy SQL Server 2005 to be used as the database server.

Here comes the problem, which is that I have not touched the client application's code at all, because it doesn't need any modifications to run on SQL Server 2005, but when I try running the application and when it tries to connect to the database which has been restored on SQL Server 2005 Express Edition running on Windows Server 2003 Enterprise Edition the connection fails and the following error is thrown:

Now I am not able to figure out what is wrong, if anyone is aware of the solution to this problem then please post it here.

Some facts I would like to mention which might be useful in reaching the conclusion:

Client Application is running on Windows Vista Ultimate and SQL Server 2005 as stated above is running on Windows Server 2003 Enterprise Edition. SQL Server is set to use Windows Authentication mode only. By default use of TCP/IP protocol for connection is disabled in SQL Server 2005 Express Edition, but it has also been enabled.

ConnectionString used:

Do you get the same results if you supply a username/password rather than Integrated Security?

I think supplying username and password is not required, because SQL Server is using Windows Authentication Mode only (not mixed authentication) and if I supply the credentials then I would have to change the authentication mode? However to test what I did now is copied the client application to the SQL Server machine and changed the ConnectionString to as follows to test it locally:
And to my surprise it worked. I really don't understand what's the issue when connecting remotely through network? I even tried the Microsoft KB articles related to the error but none of them solve the problem? When the application is working locally, it indicates that there is nothing wrong with the code?

Initial guess would be that the surface area configuration for remote connections is set to "Local connections only" rather than "Local and remote connections".

I have enabled "Local and remote connections" under the Surface Area Configuration, and have also enabled the IP address to listen on for incoming connections under SQL Server Configuration Manager but still the application is not able to connect remotely whereas it is working locally still? Error while connecting remotely is again:

Any pointers? The problem is still not solved?

Have to tried running profiler to see what is actually going to the SQL server?

I can't use SQL Profiler because it doesn't come with the SQL Server Express Edition? I looked for it on Microsoft's website, but it's not available separately for download?

The problem I have run into is very vague, and it's the first time I have come across it, also the strange thing is it works locally, but while connecting to the same instance with the same application remotely it is throwing out exception?

Did you restart SQLServer after making this change?

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Yes ofcourse, a couple of times restarted but no luck. I am not able to figure out what has gone wrong? I even disabled the firewalls.