Follow the workflow in the attached PDF to diagnose the problem.
Note: If you are trying to diagnose then the above still applies, however, for point 1 refer to here. Also, when going through the attached PDF workflow you do not need to follow the "Visokio Windows Service" section.
Update: from 2.8 b313, the Windows Service installation and configuration has been improved. If you're having difficulties with the Service, install this version or later, which may resolve the issue.