Cannot run designer in pyqt5-tools

Hi,

I'm trying to start qt designer in git-bash which provided by pyqt5-tools,
but have got the following error message (also see the attached screenshot):

> This application failed to start because no Qt platform plugin could be
initialized. Reinstalling the application may fix this problem.

 

The packages installed on the Windows 10 are:

PyQt5: 5.14.2

pyqt5-tools: 5.14.2.1.7b3

 

with Python version: 3.8.2.

 

Appreciate for any help.

Tong