Thank you for updating this. I had not seen your update until the newest review (PS: github issues might be quicker). They seems to have changed things again. Let me see how to fix this.

Edit again 2019-01-27: the latest version 4.2.4 seems to work. Please double-check.
Edit again 2020-12-07: qwant itself worked right now, qwantjunior is broken. Thanks for reporting this!