WebSerial on windows, No devices found

I have tried WebSerial API on Ubuntu and Windows both.

On Ubuntu 20.04, it works well. But my customer use Windows 7. He just got 'no devices found'.

Test app is https://googlechromelabs.github.io/serial-terminal/ Chrome version is 89.

I tried it on my VirtualBox windows7x86 with binding /dev/ttyUSB0 to COM1. Windows legacy terminal programs works well, but chrome WebSerial result is same as 'no devices'. My friend's Windows 10 chrome 89 also show same result.

Could anybody help this?

Thanks