qBittorrent official forums

Last few days been having issues with stalled downloads. Changed settings everywhere that's taken hours.
Downloaded an old version got it working.
I have just realised that if I disable proxy setting, my torrent gains seeds and it starts downloading.
So then I re-enable proxy and it's fine until the next download.

Many if not most proxies don't support UDP at all.
Most also don't support ANY incoming connections.

But both UDP and incoming connections are heavily used by qBitTorrent, so speeds are horribly impacted...even prevented when the only trackers are all udp-based ones.