Can we still expect any feedback from you? Otherwise this thread will be closed.
How can I?
I mean: YOU have chosen some SECRET credentials on your host side when creating the database. So how should I verify whether you made a mistake while entereing the same credentials when installing Ossn?
Ok, I just had a look onto your site:
the database connection can't be established!
So, open the file
configurations/ossn.config.db.php and verify that
$Ossn->user = 'your_database_user'
$Ossn->password = 'your_database_password'
are matching with the credentials you created on your host before installing Ossn.
If you can't find any typos make sure that your database user has been granted ALL permissions