Red Hat Bugzilla – Bug 1473748
Qbittorrent 3.3.13 web API does not work with custom clients.
Last modified: 2017-07-21 14:25:27 EDT
The issue is that since 3.3.13 it only accepts the requests there headers 'refer' and 'Host' are same. Allegedly it was fixed in 3.3.14
Information from those threads: