@brettw97 ...
There are 2 ways and reason why you can't download ...
Queueing - [8/5 default] you can change this setting behavior ...
Click on Options/Preferences-QueueingSettings - change the number of active torrents [upload and download] ...
Or right click on torrent [Force Start] ...
You have too many torrents running and reach your download limit ...
Stop leeching torrent to Free Slot ...