Here is a high-quality article on the issue you’re facing with Metamask and Web3.js on Binance Smart Chain (BSC):

Error: Unknown Account in Web3.js on Binance Smart Chain (BSC)

As a user of decentralized applications (dApps) built on top of the Binance Smart Chain (BSC), you’ve likely encountered the frustration of encountering errors when interacting with smart contracts. In this article, we’ll delve into the issue you’re facing and provide a solution to resolve it.

The Issue: Returned Error “Unknown Account”

When you execute a method call on a Metamask-enabled contract using Web3.js on BSC, such as nftMintingContract.methods.mint(account, cid).send({from: account}), the returned error is typically “unknown account”. This error indicates that the transaction failed due to an unknown or unauthorized account being used.

Understanding Account Management in Metamask

In Metamask, accounts are managed as private keys. Each account has a unique key pair (public and private) that’s stored on your wallet. When you create an account, it’s assigned a public address. However, when you send transactions to the contract using Metamask, the account used is not necessarily the same one you created with.

Why the Unknown Account Error Occurs

There are several reasons why you might encounter this error:

• Different Account Used: When you execute a method call on a contract using multiple accounts (e.g., from different wallets or with different keys), Metamask treats them as distinct accounts. This is because each account has its own private key, which gets used for signing transactions.

• No Reentrancy Protection

  

  : Some contracts may not have reentrancy protection enabled in their smart code. This means that if you call the mint method with an unknown account, it can potentially be called multiple times by other accounts (even though they’re using different keys), leading to unexpected behavior.

Solving the Unknown Account Error

To resolve this issue, follow these steps:

• Verify Your Account: Make sure your Metamask wallet is correctly configured and linked to your BSC account.

• Use a Single Account for All Transactions: When possible, use the same account (public address) for all transactions. This ensures that you’re always sending from the correct account.

• Enable Reentrancy Protection

  : If your contract doesn’t have reentrancy protection enabled, consider enabling it in its smart code to prevent unexpected behavior.

• Use a Different Account for Test Transactions: When testing new contracts or features, use a different account (public address) for test transactions.

Code Example

Here’s an example of how you can modify your code to resolve the unknown account error:

const contract = new Web3.eth.Contract('...');


contract.methods.mint(account, cid).send({from: account})

  .then((result) => {

    console.log(result); // Mint successful!

  })

  .catch((error) => {

    if (error.code === 'InvalidAccount') {

      console.error('Unknown account used for transaction:', error);

    } else {

      throw error;

    }

  });

By following these steps and using a single account for all transactions, you should be able to resolve the “unknown account” error when interacting with Metamask-enabled contracts on BSC.