Cannot connect to SQL Server with Windows authentication from C#

Question

I want to connect to SQL Server 2016 using Windows authentication.

I am using C# with this connection string

Server=192.168.1.12,14331;Database=master;Integrated Security=true;Timeout=30

or

Server=serversql\newinstance;Database=master;Integrated Security=true;Timeout=30

The error is a timeout connection.

When using connection with SQL Server authentication like this:

Server=192.168.1.12,14331;Database=master;User Id=***;Password=****;Timeout=30

everything is ok.

Source code C#

var constr = "<connection string>";

using (var connection = new SqlConnection(constr))
{
    var command = connection.CreateCommand();
    command.CommandType = CommandType.Text;
    command.CommandText = "SELECT 1";
    command.CommandTimeout = 0;

    connection.Open();
    command.ExecuteNonQuery();
}

But when I am using SQL Server Management Studio to check connection to the SQL Server instance with Windows authentication, it is ok. Using alias or Ip address does not help the error.

I don't understand why I get this error ...

Help me please! Thanks you everyone!

UPDATE: If I use connection 1 with IP and port, there is an error:

Login failed. The login is from an untrusted domain and cannot be used with Windows

UPDATE: Instance SQL installed on other PC the same network LAN with My PC. I'm checked Log Viewer on PC install instance SQL but no record log.

Answer 1

I'm not sure it works for you, but you can try it:

SqlConnection cnn;
public connect(){
    string strConnect = @"Data Source=192.168.1.12,14331;Network Library=DBMSSOCN;Initial Catalog=master;User ID=****;Password=*****";
    cnn = new SqlConnection(strConnect);
    try
    {
        cnn.Open();
    }
    catch(Exception)
    {
        // connect failed
    }
}
public void ExeQuery(string query){
    // query="select * from tblA"
    SqlCommand sqlCmd = new SqlCommand(query,cnn);
    sqlCmd.ExecuteNonQuery();
    sql.Dispose();
}