argis 9.3 to arcgis 10.2 arcobjects connection AutomationException: 0x5 - Access is denied. in 'Invoke'

A legacy code, written in 9.3, made connections to the server via the following code

public String connect(String domain, String user, String password) {
    new ServerInitializer().initializeServer(domain,  user, password);
    ServerConnection connection;
    try {
        connection = new ServerConnection();

        connection.connect(url);
        return "ok";
    } catch (IOException e) {
        return e.getMessage();
    }       
}

This works fine with a 9.3 server, however, when i try to connect to a 10.2, all i get is:

AutomationException: 0x5 - Access is denied. in 'Invoke'

Have they changed the way to connect in 10.2, or am i missing something?