Asp.Net The network path was not found - asp.net

Question

I'm trying to publish an ASP.NET website with MSSQL DB connection in it. I can use the IP address, user id and password parameters what the hosting service gave me to access the database in my MSSQL server. I can access the database in MSSQL server without a problem but when I tried to add connectionstring to my web.config file with same parameters, it showing me this error message. I tried almost anything to fix but no luck. This is my error code and stack trace, thanks in advance.
This is my connection.cs file which im using for db queries.myDB my ID etc. are just for representation
SqlConnection baglanti = new SqlConnection("Data Source=serverIP; Initial Catalog=myDB; User ID=myID; Password=myPass; Integrated Security=false");
baglanti.Open();
SqlConnection.ClearPool(baglanti);
SqlConnection.ClearAllPools();
return (baglanti);
And this is my connection string file.myDB my ID etc. are just for representation
<connectionStrings>
<add name="TstConnectionString" connectionString="Server=serverIP; Initial Catalog=myDB; User ID=myID; Password=myPass;Integrated Security=false" providerName="System.Data.SqlClient" />
</connectionStrings>
and there is the error section
Server Error in '/' Application.
The network path was not found
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.ComponentModel.Win32Exception: The network path was not found
Stack Trace:
[Win32Exception (0x80004005): The network path was not found]
[SqlException (0x80131904): 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)]
System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData, DbConnectionPool pool, String accessToken, Boolean applyTransientFaultHandling) +821
System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions) +332
System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions) +38
System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) +699
System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) +89
System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection) +426
System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection) +78
System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection) +191
System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions) +154
System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions) +21
System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource`1 retry) +90
System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry) +443
System.Data.SqlClient.SqlConnection.Open() +96
tstSite.esqbaglantisi.baglan() +38
TstSite.Default.Page_Load(Object sender, EventArgs e) +32
System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +51
System.Web.UI.Control.OnLoad(EventArgs e) +95
System.Web.UI.Control.LoadRecursive() +59
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +780
Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.7.2106.0`