There are several possible reasons why you might not be able to play torrent videos.
Unsupported format (CODEC): This happens when you try to stream or play a video or audio format that is not supported by your player.
Low number of seeders: Seeders are those who continue to share the file after it has been downloaded. The more seeders there are, the smoother the streaming will be. Try downloading torrents with many seeders.
Low number of peers: Peers are those who continue to download and upload at the same time. The more peers there are, the smoother the streaming will be. Try streaming torrents with many peers.
High number of leechers: Leechers are those who download the file but do not share it. Files with a lot of leechers will slow down your streaming speed. Avoid files with a lot of leechers.
Slow internet speed: Check your Wi-Fi interference, your current client version, and your client’s speed settings to improve your internet speed.
Not enough trackers: Consider adding more trackers to your torrent client.
Blocked by ISP: This means your network is blocking torrent files or blocking your outgoing port (To check this, if you are able to download a torrent on another network, then your ISP is blocking). To fix this issue, you need to change the port number or you can use a VPN.
If you are downloading high-quality formats that are not supported by your hardware, then they will not stream. In that case, you need to download a dedicated player from the app store and get the stream link from the 
Torrent Pro app and paste it into the dedicated player to work.