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Connecting to a remote SQL Server (SQLExpress) gives "network-related" error, but works using Server Explorer in Visual Studio

I am using NET 6.0 and I cannot make it work.
I am trying to connect using:
var builder = new System.Data.SqlClient.SqlConnectionStringBuilder
{
DataSource = $"{ip}\\SQLEXPRESS, 1433",
InitialCatalog = "xxx",
UserID = "user",
Password = "pass"
};
SqlConnection thisConnection = new SqlConnection();
thisConnection.ConnectionString = builder.ConnectionString;
thisConnection.Open();
However, I keep getting this
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: TCP Provider, error: 0 - No connection could be made because the target machine actively refused it.)
Using exactly the same code on Netframework 4.8 works. Anybody care to explain why? Using the same machine as above, if I use the Server Explorer in Visual Studio then the connection is successful. Also works using Python. I tried ussing the connection string from the Server Explorer connection string and still doesn't work. The connection string from that works using the Server Explorer:
Data Source=xxx.xxx.xx.xx\sqlexpress;Initial Catalog=database;Persist Security Info=True;User ID=sysdba;Password=****
Here is the Server Explored connected:
And the properties:
And then:
SqlConnection conn = new SqlConnection();
conn.ConnectionString = #"Data Source = xxx.xxx.xx.xx\sqlexpress; Initial Catalog = database; Persist Security Info = True; User ID = sysdba; Password = ******";
conn.Open();
But still fails to connect.
I also set the port to 1433 like suggested in Cannot Connect to Server - A network-related or instance-specific error and restarted the service
Also
And still fails to connect using the SqlConnection() (still works using the Server Explorer).
What am I doing wrong?
The SQL Server uses SQL Server Authentication, no Windows Credentials. I connect using IP\sqlexpress.
It doesn't seem to be a network related issue, like I saw in other answered questions, since it is working using the Server Explorer in Visual Studio and also in Python.

I was facing the same issue (Net 5.0). You can use the Connnected Services, which is a collection of tools in Visual Studio that will help you connect to the database. I believe this may be a different approach, but it should work since visual studio will be creating the connection string (same was as per Server Explorer).
https://learn.microsoft.com/en-us/visualstudio/data-tools/add-new-connections?view=vs-2022
https://learn.microsoft.com/en-us/visualstudio/azure/overview-connected-services?view=vs-2022

connection to MySql database on host

I have a problem regarding connecting to my database that is located on my website host server. I have watched few tutorials, took a look on few articles here on stack overflow and read official mysql documentation, and i steel can't connect to it thru my c# console app. This is my code:
string connstring = string.Format("Server=www.vm-consult.com; Database=vmconsul_sitedatabase; Uid=vmconsul_mijovicpetar; Pwd=mypassword");
MySqlConnection connection = new MySqlConnection();
connection.ConnectionString = connstring;
connection.Open();
I have also went to c panel in remote MySQL tab and set "%" to my remote sql hosts.
All the parameters for con string are correct. In server in connection string I also tried to set IP address, did not change anything.
This is exception I get(on the last line: connection.open()):
Unable to connect to any of the specified MySQL hosts.
Any suggestions appreciated. Thanks.

Check connectivity with
telnet www.vm-consult.com 3306

I needed to contact my host provider to enable external connection to the database. Thanks everybody.

Sql connection string via SqlClient

I have an issue trying to manually connect to a sql server on my network.
I have a web API with a conn string that works fine, I have a VS2015 winforms project i set up to test the conn using the VS tool to connect, this also works fine.
However when i try to connect via SQLconnection it fails and says the server cannot be found or isnt accessable.
So heres the test code...
string connectionString = #"Data Source=test1\test1;Initial Catalog=my_test;Integrated Security=True;";
using (SqlConnection connection =
new SqlConnection(connectionString))
{
// Create the Command and Parameter objects.
SqlCommand command = new SqlCommand("", connection);
// Open the connection in a try/catch block.
// Create and execute the DataReader, writing the result
// set to the console window.
try
{
connection.Open();
SqlDataReader reader = command.ExecuteReader();
while (reader.Read())
{
Console.WriteLine("\t{0}\t{1}\t{2}",
reader[0], reader[1], reader[2]);
}
reader.Close();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
Console.ReadLine();
}
Now i dont really care about results or anything i simply need to establish a connection. I cant figure out why it throws this error, when my Web API works and the VS tool for connection to DBs works fine too.
I have checked the server and enabled named pipes too just to make sure.
Any ideas?
EDIT:The error i catch...
{"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)"}
happens after about 15 seconds trying to open the connection.
The thing is this connectiin string i tried is the exact same string used via the SQL tool, I did this so i knew i had a valid string.
ODBC connection also falls over with the same message.
I checked from my machinbe is i can listen to port 1433 but it says the server isnt listening.
However looking at the server its set to dynamic ports with a range of any to 41934, so im at a loss as to why it says its not listening evenb though its to dynamic ports
EDIT2: Well, must be permissions or drivers... just tried the exact same code and worked instantly...
This is diving into the realm of the unknown i feel. might ask for deletion of the question if no solution is found

I think that i see the problem:
string connectionString = #"Data Source=test1\test1;Initial Catalog=my_test;Integrated Security=True;";
Integrated Security is used for local logins, You could make an account in the database and change the connection string to:
string connectionString = #"Data Source=test1\test1;Initial Catalog=my_test;User id=<Username>;Password=<Password>;";
I hope this helps!

Visual Studio connects to database, but application within using the same connection string cannot

Using SSMS and Visual Studio 2015's Server Explorer tab under Data Connections, I can execute queries on remote server KOSH without issue. Why is the MVC application running locally in Visual Studio/IIS Express unable to do the same?
Using VS2015's connection Properties, I get its connection string:
Data Source=123.456.78.9;Persist Security Info=True;User ID=Foo;Password=Bar
Using that connection string, the MVC application is greeted with:
"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)"
Inner exception message:
"The network path was not found"
I know the server/firewall/network settings are correct. That leaves the application.
using(var connection = Database.Connection(conInfo.ConnectionString, provider)) {
// rowCountSql: SELECT SUM(rows) TM_ROWCOUNT FROM sys.partitions
// WHERE object_id = object_id(#tableName) and index_id IN (0,1)
// Any other SQL yields same error
var countTask = connection.QueryAsync(rowCountSql, new { tableName = Editor.TableName });
}
Async is used because the Oracle version of the query can take several seconds to return.
The application should be correct because it connects to the same server from home (also the server's location) and to identical databases in remote data centers running 2008R2 to 2014 without a problem.
Database.Connection() is:
// This is unlikely to be the problem as it is very well tested
public static DbConnection Connection(string connectionString, string databaseProvider) {
DbProviderFactory databaseFactory = DbProviderFactories.GetFactory(databaseProvider);
DbConnection connection = databaseFactory.CreateConnection();
if(connection != null)
connection.ConnectionString = connectionString;
return connection;
}
I bet I am missing something simple, but I would be grateful for help on what that could be.

As I said in comments, maybe the piece of your code:
conInfo.ConnectionString
does not contains the correct connection string you want.
Check it out

ODBC connection to SQL Server 2012 LocalDB instance

We have a "legacy" application, which uses ODBC connections to an underlying database, which can be Access, Oracle or SQL Server. For unit (or, perhaps more properly, "integration") test purposes, I'd like to hook up a SQL Server 2012 LocalDB instance. However, I cannot figure out a correct ODBC connection string to use.
I have tried:
[TestMethod]
public void OdbcConnectionToLocalDb()
{
string connectionString = "DRIVER=SQL Server Native Client 11.0;Trusted_Connection=Yes;SERVER=(localdb)\v11.0;Description=LocalDB;";
using (OdbcConnection connection = new OdbcConnection(connectionString))
{
using (var command = new OdbcCommand("select * from Person", connection))
{
connection.Open();
// ...
}
}
}
However, when the connection is opened, the following exception is thrown:
System.Data.Odbc.OdbcException: ERROR [08001] [Microsoft][SQL Server Native Client 11.0]Named Pipes Provider: Could not open a connection to SQL Server [67].
ERROR [HYT00] [Microsoft][SQL Server Native Client 11.0]Login timeout expired
ERROR [08001] [Microsoft][SQL Server Native Client 11.0]A network-related or instance-specific error has occurred while establishing a connection to SQL Server. Server is not found or not accessible. Check if instance name is correct and if SQL Server is configured to allow remote connections. For more information see SQL Server Books Online.
Is it possible to connect to a SQL Server 2012 LocalDB via an ODBC connection/driver? Is it possible to connect to a specific file?
[EDIT]
Garrett points out it is possible, great. I must have the connection string wrong, so my question really should be: what should the connection string be?

You need to specify your connection string like this:
Provider=SQLNCLI11.1;Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=TestDB;Data Source=(localdb)\v11.0
The main thing I think is that you reference it as a data source rather than server.

Yes, it's possible. Make sure you install the latest driver: SQL Server Native Client "Denali" (for ODBC and OLE DB).
Look here for more info:
http://blogs.msdn.com/b/sqlexpress/archive/2011/07/12/introducing-localdb-a-better-sql-express.aspx