I see that you are using Linux… Also, that error message suggests that you are using Transmission. When Transmission says that a torrent is "Stalled", generally it means that there is no activity on the torrent within the last however long your threshold settings are set to. This is not a problem necessarily, as it just means that there has been no activity.
What catches my attention though is that the tracker says you are using a different torrent client. I'm not sure how you'd check the tracker state or error message in the torrent client the tracker says you are using (or otherwise have used). I would imagine that the problem is that you're either not able to resolve the tracker's IP address. This is the most common issue with tracker communications, aside from the tracker timing out occasionally. To ensure you are able to resolve the IP address properly, I would suggest changing to Google DNS by using 8.8.8.8 and 8.8.4.4 as your DNS server settings.
