This is a very common issue, apparently. If you are in Suramar, it will only use lure from Suramar. Blizzard didn't make it very easy to determine which is which. If you are fishing up stuff for "Open Ocean" (indicated on first page), it won't use that stuff unless you are on "Broken Shore" or "The Great Sea". If you are trying to fish up Suramar stuff, you are in the wrong spot. If you want to fish up Open Ocean stuff afk, you need to go to somewhere that lists those 2 Zones on your map.
All people have told me is "I am in Suramar", but haven't specified. If there's a sub-zone, I can add, but if I add Suramar as a Zone for Open Ocean items and you are in a different spot, the items may not work there and will be wasted.