According to a discussion on the official forums, this issue is caused by the Windows Vista or the server version you're trying to connect to. Users reported that no error was displayed for the Windows XP version. However, I recommend turning off the application then check the username and password. The error can be assigned to this cause as well. After everything is configured properly, attempt to initiate a new connection. If it does not work, contact the the developers at the following email address: support@rangersuite.com