"Couldn't update search engine plugin. Plugin is not supported"

[Giuseppe]

I try to install any search add-on, but I always get a %subj% "Search plugin update" message. The error appears both when you select a link to a * .py file, as well as to it saved to the local computer.

qBittorrent v4.2.5 / Search plugins / Install a new one / Plugin source. Search plugin source: Local file
Python 3.9.0 (tags/v3.9.0:9cf6752, Oct 5 2020, 15:34:40) [MSC v.1927 64 bit (AMD64)] on win32, Python Launcher 3.9.7217.0
Microsoft Windows 10.0.19041.508.

[Peter]

- I think Python 3.9.0 might be just too new. Maybe I am not correct but it's sooo recent and Python upgrades always break something. I personally still run 3.7.x because I fear something might break and I don't need 3.8 stuff myself (yet). Python upgrades are like that.
- Where does this message appear? In qBittorrent as a pop-up? Could you attach a picture?

[Giuseppe]

It's strange, but now in the window of installed search engines, a list of dozens of them is displayed. When I wrote the first message, the list was empty. Unfortunately, I cannot tell if this happened after rebooting the application, PC, or other activity.