can create NFT but can't Buy from marketplace, nothing happens

[latonet]

Hi, I can create NFTs, they show in dashboard for the metamask account and marketplace but cannot buy, nothing happens with Buy button. Thanks

[latonet]

This is the code for the Buy button in the NFT box. There's nothing there to make it execute something to Buy the NFT.

button class="w-full bg-pink-500 text-white font-bold py-2 px-12 rounded">Buy</button

[61go]

this is built by react. I read the code, it supposed to be executed . but I cannot buy either.

[latonet]

this is built by react. I read the code, it supposed to be executed . but I cannot buy either.

Yes, but why doesn't it work? What's going wrong.

[janzheng]

This is happening because of a Mumbai error, outputting the wrong contract address. This causes the NFT contract to not approve the Marketplace's contract address to sell the NFTs. Redeploy with this script, by replacing main() in deploy.js with:

async function main() {
  const [deployer] = await hre.ethers.getSigners();

  console.log(
    "Deploying contracts with the account:",
    deployer.address
  );

  let txHash, txReceipt
  const NFTMarket = await hre.ethers.getContractFactory("NFTMarket");
  const nftMarket = await NFTMarket.deploy();
  await nftMarket.deployed();

  txHash = nftMarket.deployTransaction.hash;
  txReceipt = await ethers.provider.waitForTransaction(txHash);
  let nftMarketAddress = txReceipt.contractAddress

  console.log("nftMarket deployed to:", nftMarketAddress);

  const NFT = await hre.ethers.getContractFactory("NFT");
  const nft = await NFT.deploy(nftMarketAddress);
  await nft.deployed();


  txHash = nft.deployTransaction.hash;
  // console.log(`NFT hash: ${txHash}\nWaiting for transaction to be mined...`);
  txReceipt = await ethers.provider.waitForTransaction(txHash);
  let nftAddress = txReceipt.contractAddress

  console.log("nft deployed to:", nftAddress);
}

[latonet]

Thanks for this. I've also replied in your post.

[latonet]

Hi, still can't Buy, nothing happens. I updated deploy.js with your code, it deployed to new contract addresses, works like before but i can't Buy, only creates NFT in marketplace and can see it in created items.

This is the Buy buttton code: <button class="bg-green-500 hover:bg-green-700 text-white font-bold py-2 px-4 rounded-full" onClick={() => buyNft(nft)}>Buy</button>

Thanks

[latonet]

Just noticed the transaction hash output for me is for the NFT contract not the Market contract ........ how can i check the transaction hash for the Market contract?

I updated deploy.js, reinstalled dependencies and deleted artifacts folder, recompiled. Still can't buy from marketplace, can create NFTs to show in it.

How do i redeploy to the same contract? When i run the script it creates a new contract with same problems.

Thanks

[latonet]

this is built by react. I read the code, it supposed to be executed . but I cannot buy either.

Did you fix the problem? The code change still doesn't let users buy from my test site.

[janzheng]

this is built by react. I read the code, it supposed to be executed . but I cannot buy either.

Did you fix the problem? The code change still doesn't let users buy from my test site.

The error I found has nothing to do with the React code, which you posted. The button does what it's supposed to do (fire the function to buy) — it's the smart contract that's set up wrong, because of a bug on the Mumbai test net. Basically what's happening is that the Market.sol smart contract is not allowed to perform the buy operation, because the Market contract doesn't have access.

On blockchain, you can't deploy to the same contract — every time you deploy, you're "minting" a new contract, so you always get new addresses. My fix to the deploy.js code is that by looking at transaction hashes, you can find the RIGHT address to the Market contract (that's minted first) — this address is passed to the constructor of the NFT.sol contract, which adds the market's contract address to the "allow" list. Without the right addresses, you'll have problems like buying.

Looks like you're still having address issues. The way I found the error was — I had to go to Polygonscan, put in my wallet's public key that I used to mint the Market and NFT tokens, and find the smart contract addresses. Make sure that those addresses match up with what's output from deploy.js — if it doesn't, it means your buy function won't work, and you have to dig further.

I'm actually really new to Polygon and web3, so I might be completely wrong in my assessment and understanding haha...

One Mumbai testnet fixes their bug, this error should go away too. (But you'd have to redeploy)

[latonet]

From what I've seen, and already done what you suggest on polygonscan, both the contracts match what deploy.js outputs. But the buy function still doesn't work.

The transaction hash output is for the NFT contract not the Market contract. How do I output/see the transaction hash for the Market contract?

I don't know why your code change doesn't work. Even what some others posted on a more in depth posts on this issue doesn't work and it's similar to your code.

It's annoying that the fixes don't work !!!

Thanks