A network-related or instance-specific error occurred when connecting to remote server in ASP.Net

Hi,

I using  VS2013  and Sqlserver 2012 express edition for the testing. What i did was  i connected  the database with frontend using server explorer and copied the connection string. when try to test the connection through the code it throws an error.

Here is my sample code:

string connstring = "Data Source=170.30.149.34;Initial Catalog=Sample;User ID=sa;Password=test";
            using (SqlConnection conn =  new SqlConnection(connstring))
            {
                conn.Open();
               Response.Write("Connected");           

            }

Error:

An unhandled exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll Additional information: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)

Any suggestion please