Torrent Health: One of the main reasons is due to poor Torrent health. If your Torrent doesn’t have enough Seeders and Peers, then the chance of downloading is very low. So make sure your Torrent health is good.
Slow internet Speed: Check your Wi-Fi interference, your current client version, and your client’s speed settings to improve your internet speed. (And also check your internet speed at https://speedtest.net or https://openspeedtest.com)