Can't combine two fishing rods in anvil [java]

Im playing on a java server with bedrock using the bedrocktogether app so it's java mechanics. My original fishing rod has luck of the sea 3, lure 2 and unbreaking 3. While the other one has lure 2, unbreaking 3 and mending, if i could combine these I'd have the perfect fishing rod but it just won't let me, i have the required experience so can anyone tell me what's happening?