uga
Ah great you found that out already (as of other thread). So indeed Chromium based browsers are an issue. I faced the same with Opera, while on Edge it worked well.
Since the qBitTorrent package from Debian Stretch repo has not changed since 2017, and I didn’t face this issue earlier, it must be due to some later Chromium change. I wonder if this has been fixed already with newer qBitTorrent versions… Either we need to install a newer version from a different source (or source build) or we at least need to inform users via our online docs.