I have the exact same setup (used, original wiseway, Wood&Sons pellets) and only sometimes have this issue.
One thing I tried which did help was to add about an 8" hopper extension using sheet metal/rivots. I think the extra weight from additional pellets helps unclog the traffic jams more often, but it still happens from time to time. I previously tried putting down aluminum tape inside the hopper to make it slicker, but the adhesive didn't last long and didn't prevent the jams.
Hope you have a better experience soon!