I had exactly the same problem. I was tearing my hear out trying to get this thing working.
Windows 10 pc which was wired and Mac mini m4 which was WiFi.
I did get it to work though after hours of trial and error
i ended up buying a mini network hub which connects to my isp router…. Connected both to the hub via Ethernet which is 1gbit. disabled WiFi on Mac and disabled both Mac and windows firewalls…. And bingo! The problem has gone they found each other at last
one thing I hate about this app, you can only transfer files / folders to the actual Mac internal storage and not even fast thunderbolt storage….