This isn't the bittorrent protocol fault, because the protocol specifies no server at all, it was made to not have an central server, only "normal computers TO normal computers".
If you would like to understand how torrent protocol works, please start by:
Seeing this little fast-resume png image:
https://drive.google.com/open?id=0BxFQ19JuGfrjWUVyTXRTcTczczQ
The small SQUARES are packets/messages/data, specifically Pieces from the technical protocol.
Understand that, every byte you receive or send, are to other humans, that means that their computers must be online and able to be connected or able to connect into the specific ports, "router ports, internet ports, specifically the bittorrent protocol data, which requires one port open". There is no server, there is no WEB/HTTP accessible for you to download, but there is an feature called Web Seed which I will not get into details, and you will not be an Web Seed for not wasting your time.
Peers: ones that download the torrent AND upload some of the parts that has received.
Seeders: ones that already downloaded and are sending to others, because they want and that's all.
Leechers: in that specific context, means the ones that download/downloading and doesn't care about anyone else.
Maybe the torrents you are trying to download has zero peers and zero seeders; maybe your DHT isn't getting peers because you have low amount of torrents and peer accessibility; maybe your ISP is blocking your torrent protocol because it has detected piracy after some hours; maybe you haven't allowed an inbound port into the router; maybe the tracker you are trying to access is forever down; maybe there are seeders, but they haven't allowed an inbound port into their router neither you have allowed into your router.
Important topics: introduction, 1.1, 4, 4.1, 4.2
https://en.wikipedia.org/wiki/BitTorrent_tracker
