Are you using Transmission 3.0 by chance? Some users have had to roll back to the previous version (2.94) to be able to work with the SSL tracker.
As for the blocking, there's not much we can do, as the DDoS protection is a 3rd party service, for which we are not able to configure or tweak.
Hello i tried with the latest version of μTorrent on my PC and also with an embedded torrent download client on my router which is "Freebox Bittorrent Downloader 2.0"