Can't connect to SQLSERVER 2008 R2 EXPRESS

Question

I'm in SQLSERVER (2008 R2 EXPRESS) administrators list. I'm in administrator role on my machine. And I can manually connect to SQLSERVER (via Management Tools) using ServerName (in my case it's S-PROG-T\SQLEXPRESS). During installation I decided to use only Windows Authentication mode. I can't connect to SS.

Error message is: Login failed for user S-PROG-T\admin. Cannot open database 'ProjectDB' requested by the login.

I'm using the following configuration for NHibernate:

<session-factory>
    <property name="connection.provider">
        NHibernate.Connection.DriverConnectionProvider
    </property>
    <property name="dialect">
        NHibernate.Dialect.MsSql2008Dialect
    </property>
    <property name="connection.driver_class">
        NHibernate.Driver.Sql2008ClientDriver
    </property>
    <property name="connection.connection_string">
        Data Source=S-PROG-T\SQLEXPRESS;Initial Catalog=ProjectDB;Integrated Security=SSPI
    </property>
    <property name="show_sql">
        true
    </property>
    <mapping resource="Project.Domain.Model.Entities.Mappings.Vehicle.hbm.xml" assembly="Project.Domain" />
 </session-factory>

And I've tried to connect using .\SQLEXPRESS data source. Inbound rules don't restrict SSMS.

What's wrong? Thanks!

EDIT: Unit tests

Everything (nhibernate configuration, and schema export trial) starts inside my unit test (I don't know if this matters).

[TestFixture]
public class VehicleFixture
{
    [Test]
    public void TestSchemaExport()
    {
        new SchemaExport(new Configuration().Configure()).Execute(false, true, false);
    }
}

EDIT: Log information

I discovered the next information inside a log (path: %ProgramFiles%\Microsoft SQL Server\MSSQL10_50.SQLEXPRESS\MSSQL\Log\):

Error: 18456; State: 38.

Login failed for user ‘S-PROG-T\Admin’.

Reason: Failed to open the explicitly specified database.

According to the article: http://sql-articles.com/articles/troubleshooting/troubleshooting-login-failed-error-18456/ database doesn’t exist or login doesn’t have access to the database.

I'm totally confused. Should I have created the database (manually) before I tried to export schema (sorry if the question is silly)?

EDIT: Using Mixed Authentication mode

I've set Mixed mode Authentication and created new login with serveradmin & sysadmin roles. But still the error message is the same, except for user name. Again I can manually do the same thing (connect and create db) with the login and its password.

Answer 1

Ok. I misunderstood the whole process. Everything's ok with Authentication and rather with connection strings. I just thought that schema export stands for database automated-creation and then schema export. So I created a DB and successfully exported a schema.