The Driver Mode will be either MME, WDM, WASAPI or ASIO.
You find that under options>Audio in older programs or View>Preferences in the newer, X1-based programs.
I think you should use ASIO, if possible.
Also under Options>Audio or Preferences, make sure that the BOSS is listed and selected as both the Recording Device (or Timing Master) and Playback Device.
You may have to close and re-open the program after changing these settings.