Database problem -- error: 40-unable to open the connection to SQL Server

Error:

 

" / "ApplicationProgramServer error.
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Network-related or instance-specific errors occur when you establish a connection with SQL Server. The server is not found or cannot be accessed. Verify that the Instance name is correct and SQL server is configured to allow remote connection. (Provider: named pipeline provider, error:40 -Cannot open the connection to SQL Server)
Note: An unhandled exception occurs during the execution of the current Web request. Check the stack trace information to learn about this error andCodeDetailed information about the cause of the error.

 

Cause:

Because I can remotely connect to and operate on the database on SQL Server Management studio, I excluded what I said on the network and did not develop a remote connection. I carefully checked the SQL connection string

Connectionstring, found that there are brackets on the data source, although do not know the true role of the brackets, but I know that sometimes it is needed, and sometimes it is not needed, I remove the brackets to become

 

< Connectionstrings >
< Add name = " Sql2005conn " Connectionstring = " Data Source = 192.168.2.102; initial catalog = Master; user id = sa; Password = 123456 " Providername = " System. Data. sqlclient " />
</ Connectionstrings >

 

Run the program again and find the problem is gone.