I'm using a SOCKS5 vpn and I often need to change server, unfortunately after changing server it seems like I need to re-write or re-paste my authentication password in, or the proxy won't work, not even after restarting qBittorent.
I'm not 100% sure of this, and I quickly looked and the code on github and it seemed fine, but if it's not this, there is definitely something wrong with the proxy implementation, which often doesn't work as torrents don't start (0 peers found), while if I use the VPN application to apply the VPN over my whole connection, with the same server, torrents always start.