After a few hours of having fun with this module (wanted to track phones vs MAC), here is what finally worked for ME:
I added one “dummy” IP address (eg of my home NAS). Once the program saw the IP address, it also found all the MAC addresses.
NO idea why, so don’t knock this. Banged my head against it for hours.
[then again, maybe the black cat I sacrificed helped too]
Anyway, that’s my 2c.
K