Caot complete Google Drive authentication in exe file

I have a python program that requires Google Drive Authentication. When I run it in Windows from the command Line

python xxx.py

it works perfectly.

I have created an exe file using pyi-build (PyInstaller). When I double click on the exe file it takes me to the authentication page. I click on 'Allow' and I get the exception 'Google Drive not authenticated'

The relevant code follows

        gauth = GoogleAuth()
        try:
            gauth.LocalWebserverAuth()
        except:
            dlg=wx.MessageDialog(None, 'Google Drive not authenticated', 'xxxxx', wx.OK|wx.ICON_EXCLAMATION)
            result=dlg.ShowModal()
            self.Close()

Can anyone suggest what is amiss?