I have just attempted to upgrade to Polyphone Sound Font Editor (PSFE) -Win 64 Version - from 2.0.1 to the current version 2.2.0.
In the new version neither the virtual keyboard in the app or my midi keyboard via a Behringer UMC404HD USB interface work. The settings from both versions appear to be the same. With the UMC404 disconnected, no other software running and after a reboot, clicking on the piano keys of the virtual keyboard with the mouse produces reasonable looking values for Key/Velocity/Aftertouch on the status bar but no sound. With PSFE still running if I click on a midi file that opens the default windows Media Player it plays the midi file as expected so there doesn't appear to be any problem with the midi player on my system.
There are other applications on my system which also use midi including MuseScore, Band-In-A- Box and Reaper but these were all closed and a reboot performed prior to this test.
I have reverted back to the previous version of PSFE and it works fine with both the virtual keyboard or the midi keyboard and interface.
My computer is a Toshiba Satellite L50B laptop with 16Gb Ram and SSD drive running Windows 10 Home operating system Version 21H1