After many attempts to determine why my scheduled recordings were failing, I noticed my (win10) taskbar speaker icon was muted/no sound/no playback devices/etc.
This generally happens overnight, while charging my devices when; Either I or windows turn the devices off while charging- Speakers, BlueTooth headsets, USB Headsets, etc. Coincidentally and annoyingly this is my PLAYON 'off-peak' hours period when I try to make most of my recordings.
If all devices are turned off during this period, (or any other when a recording is attempted) PLAYON will fail to recognize that there are any audio devices on the system and fail to make the scheduled recording.
Now, I have at least one audio device on and running (even if I don't use it) 24/7 and PLAYON failed recordings rarely occur.
Hope this helps someone.