There are multiple causes of uTorrent not starting the download. uTorrent might not start the download because:
- there is no seeder or peer available. > search for alternative torrent with other tracker
- firewall blocks uTorrent > open your favorite firewall application and allow uTorrent to communicate with Internet
- you need to log-in on the tracker before downloading. > log-in if you have a username and password to the tracker who manages the torrent file
- ISP blocked uTorrent protocol. > you need to ask permission from your ISP
- incorrect settings in uTorrent > enable protocol encryption in uTorrent settings
- port is not open and uTorrent can't connect. > if you're using a router, open the port from the NAT > Port Forwarding section.
You need to check each case and take one action at a time to eliminate these factors.