I believe I've found a bug:
I've installed QAP v11.6.4.2.1 (64bit) using the installer/auto update
I used the Add Active Folder / Website for this site:
https://pixabay.com/
When I press [Get website icon]
or [Enter favicon.ico URL] and then enter
https://pixabay.com/favicon.ico, I get the message saying
The icon for this website is not available or is invalid: https://pixabay.com/favicon.ico
Yet, if I open a new tab in my browser and paste, https://pixabay.com/favicon.ico into the URL and press Enter, the icon shows up.
I then:
- right click on it and save it as an image
- click on the Change icon link in QAP
- select the image I saved in step 1
and everything works just fine.