Do you subscribe to the RSN Sports Pack package? It may be that if you don't subscribe to the sports pack package, FSN New Orleans Pelican live feeds are blacked out. Where I live (East Tennessee), I am in markets that are claimed by both the Atlanta Braves and Cincinnati Reds. When I subscribed to Sports Pack, I had access to both teams' live feeds of games. When I dropped Sports Pack for awhile, I only had access to Braves games since FSO was considered a secondary market.
Wondering if both Memphis and Atlanta are considered your primary RSNs (and this is why you get live feeds of their games), and New Orleans is considered a secondary RSN (which means that you would only have access to their live feeds if you subscribe to the Sports Pack).