Buying Orders With Opensea-Js Silently Quitting

Question

I'm currently trying to buy something on Opensea with opensea-js.

I've set up my wallet with a subprovider and I can actually create bids on Opensea with opensea-js, so I think it's authenticated properly.

The problem is when I try to buy a sell order:

    const my_buy_order = await seaport.api.getOrder({
      asset_contract_address: contract_addr, //contract address of NFT
      token_id: token_id, //token of NFT
      is_english: false, //buy now
      side: OrderSide.Sell
    }).then(function(order) {
      if (order) {
        seaport.fulfillOrder({
          order: order, //feed order into fulfillOrder 
          accountAddress: OWNER_ADDRESS //my wallet address
        })
      } else {
        console.log("Order is dead")
      }
    })

It seems to just print "Sell order is valid: true" and the program terminates without my wallet purchasing anything.