Ethers.js: Unpredictable gas limit error when sending transaction (in documentation example)

[alexreyes]

Hi. I'm following the "connecting to the DAI contract" code on the getting started documentation, and I keep on getting an unpredictable gas limit error.

For reference, here's my code:

async function interact() {
  // https://docs.ethers.io/v5/getting-started/#getting-started--contracts
  const daiAddress = "dai.tokens.ethers.eth";

  const daiAbi = [
    // Some details about the token
    "function name() view returns (string)",
    "function symbol() view returns (string)",

    // Get the account balance
    "function balanceOf(address) view returns (uint)",

    // Send some of your tokens to someone else
    "function transfer(address to, uint amount)",

    // An event triggered whenever anyone transfers to someone else
    "event Transfer(address indexed from, address indexed to, uint amount)"
  ];

  const provider = ethers.getDefaultProvider(process.env.NETWORK);

  const wallet = new ethers.Wallet.fromMnemonic(process.env.METAMASK_PRIVATE_KEY).connect(provider);

  const daiContract = new ethers.Contract(daiAddress, daiAbi, provider);
  let daiSymbol = await daiContract.symbol(); 
  console.log(daiSymbol);

  const erc20_rw = new ethers.Contract(daiAddress, daiAbi, wallet)

  // // Each DAI has 18 decimal places
  const dai = ethers.utils.parseUnits("1.0", 18);

  await erc20_rw.transfer('0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D', dai);
}

And every time this runs I get the following error:

Error: cannot estimate gas; transaction may fail or may require manual gas limit (error={"reason":"cannot estimate gas; transaction may fail or may require manual gas limit","code":"UNPREDICTABLE_GAS_LIMIT","method":"estimateGas","transaction":{"from":"0xe586C7BE1Ab861B658Ff49849ea27b0aFe0D5782","gasPrice":{"type":"BigNumber","hex":"0x47868c0000"},"to":"0x6B175474E89094C44Da98b954EedeAC495271d0F","data":"0xa9059cbb0000000000000000000000007a250d5630b4cf539739df2c5dacb4c659f2488d0000000000000000000000000000000000000000000000000de0b6b3a7640000"}}, tx={"data":"0xa9059cbb0000000000000000000000007a250d5630b4cf539739df2c5dacb4c659f2488d0000000000000000000000000000000000000000000000000de0b6b3a7640000","to":{},"from":"0xe586C7BE1Ab861B658Ff49849ea27b0aFe0D5782","gasPrice":{},"nonce":{},"gasLimit":{},"chainId":{}}, code=UNPREDICTABLE_GAS_LIMIT, version=abstract-signer/5.0.14)
    at Logger.makeError (/Users/alex/Local/Million-Dollar-NFT/NFT-contracts/node_modules/@ethersproject/logger/src.ts/index.ts:205:28)
    at Logger.throwError (/Users/alex/Local/Million-Dollar-NFT/NFT-contracts/node_modules/@ethersproject/logger/src.ts/index.ts:217:20)
    at /Users/alex/Local/Million-Dollar-NFT/NFT-contracts/node_modules/@ethersproject/abstract-signer/src.ts/index.ts:213:31
    at processTicksAndRejections (internal/process/task_queues.js:97:5)
    at async Promise.all (index 5) {
  reason: 'cannot estimate gas; transaction may fail or may require manual gas limit',
  code: 'UNPREDICTABLE_GAS_LIMIT',
  error: Error: cannot estimate gas; transaction may fail or may require manual gas limit (method="estimateGas", transaction={"from":"0xe586C7BE1Ab861B658Ff49849ea27b0aFe0D5782","gasPrice":{"type":"BigNumber","hex":"0x47868c0000"},"to":"0x6B175474E89094C44Da98b954EedeAC495271d0F","data":"0xa9059cbb0000000000000000000000007a250d5630b4cf539739df2c5dacb4c659f2488d0000000000000000000000000000000000000000000000000de0b6b3a7640000"}, code=UNPREDICTABLE_GAS_LIMIT, version=providers/5.0.24)
      at Logger.makeError (/Users/alex/Local/Million-Dollar-NFT/NFT-contracts/node_modules/@ethersproject/logger/src.ts/index.ts:205:28)
      at Logger.throwError (/Users/alex/Local/Million-Dollar-NFT/NFT-contracts/node_modules/@ethersproject/logger/src.ts/index.ts:217:20)
      at /Users/alex/Local/Million-Dollar-NFT/NFT-contracts/node_modules/@ethersproject/providers/src.ts/fallback-provider.ts:631:24
      at Array.forEach (<anonymous>)
      at /Users/alex/Local/Million-Dollar-NFT/NFT-contracts/node_modules/@ethersproject/providers/src.ts/fallback-provider.ts:613:33
      at step (/Users/alex/Local/Million-Dollar-NFT/NFT-contracts/node_modules/@ethersproject/providers/lib/fallback-provider.js:48:23)
      at Object.next (/Users/alex/Local/Million-Dollar-NFT/NFT-contracts/node_modules/@ethersproject/providers/lib/fallback-provider.js:29:53)
      at step (/Users/alex/Local/Million-Dollar-NFT/NFT-contracts/node_modules/@ethersproject/providers/lib/fallback-provider.js:33:139)
      at Object.next (/Users/alex/Local/Million-Dollar-NFT/NFT-contracts/node_modules/@ethersproject/providers/lib/fallback-provider.js:29:53)
      at fulfilled (/Users/alex/Local/Million-Dollar-NFT/NFT-contracts/node_modules/@ethersproject/providers/lib/fallback-provider.js:20:58) {
    reason: 'cannot estimate gas; transaction may fail or may require manual gas limit',
    code: 'UNPREDICTABLE_GAS_LIMIT',
    method: 'estimateGas',
    transaction: {
      from: '0xe586C7BE1Ab861B658Ff49849ea27b0aFe0D5782',
      gasPrice: [BigNumber],
      to: '0x6B175474E89094C44Da98b954EedeAC495271d0F',
      data: '0xa9059cbb0000000000000000000000007a250d5630b4cf539739df2c5dacb4c659f2488d0000000000000000000000000000000000000000000000000de0b6b3a7640000'
    }
  },
  tx: {
    data: '0xa9059cbb0000000000000000000000007a250d5630b4cf539739df2c5dacb4c659f2488d0000000000000000000000000000000000000000000000000de0b6b3a7640000',
    to: Promise { '0x6B175474E89094C44Da98b954EedeAC495271d0F' },
    from: '0xe586C7BE1Ab861B658Ff49849ea27b0aFe0D5782',
    gasPrice: Promise { [BigNumber] },
    nonce: Promise { 0 },
    gasLimit: Promise { <rejected> [Circular] },
    chainId: Promise { 1 }
  }

How can I fix this?

[ricmoo]

Does you account have DAI? In order to send a DAI from your account to another, you need to have DAI to send.

[alexreyes]

Yup, it has DAI. https://rinkeby.etherscan.io/address/0xe586c7be1ab861b658ff49849ea27b0afe0d5782

[ricmoo]

The next problem in that code example might be using "dai.tokens.ethers.eth" as your token address. I have only configured the mainnet ENS name for these shortcuts. Can you try using the entire DAI address?

[alexreyes]

I replaced the DAI ENS + the ENS in the transfer() function, and I'm still getting the same error :(

[saingsab]

Hi got the same issue!!
--------CODE:---------

const tx = await router.swapExactTokensForTokens(
        amountIn,
        amountOutMin,
        [tokenIn, tokenOut],
        addresses.recipient,
        Date.now() + 1000 * 60 * 10, //10 minutes
    );
    const receipt = await tx.wait();
    console.log('Transaction receipt');
    console.log(receipt);```

   -----ERROR Restponse---------
   ```
bsc-bot_1  | Error: cannot estimate gas; transaction may fail or may require manual gas limit (error={"reason":"cannot estimate gas; transaction may fail or may require manual gas limit","code":"UNPREDICTABLE_GAS_LIMIT","error":{"code":3,"response":"{\"jsonrpc\":\"2.0\",\"id\":10,\"error\":{\"code\":3,\"data\":\"0x08c379a0000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000000245472616e7366657248656c7065723a205452414e534645525f46524f4d5f4641494c454400000000000000000000000000000000000000000000000000000000\",\"message\":\"execution reverted: TransferHelper: TRANSFER_FROM_FAILED\"}}"},"method":"estimateGas","transaction":{"from":"0x09F574b25F6Ce593B26fFce3058E005c2c7683E9","gasPrice":{"type":"BigNumber","hex":"0x3b9aca00"},"to":"0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D","data":"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"}}, tx={"data":"0x38ed1739000000000000000000000000000000000000000000000000016345785d8a00000000000000000000000000000000000000000000000000e55936dd6b926c680600000000000000000000000000000000000000000000000000000000000000a000000000000000000000000009f574b25f6ce593b26ffce3058e005c2c7683e9000000000000000000000000000000000000000000000000000001788481eda30000000000000000000000000000000000000000000000000000000000000002000000000000000000000000c778417e063141139fce010982780140aa0cd5ab000000000000000000000000f26c66abbef5ed99eeec161e3fb1a0428d764b47","to":{},"from":"0x09F574b25F6Ce593B26fFce3058E005c2c7683E9","gasPrice":{},"nonce":{},"gasLimit":{},"chainId":{}}, code=UNPREDICTABLE_GAS_LIMIT, version=abstract-signer/5.0.14)
bsc-bot_1  |     at Logger.makeError (/home/node/app/node_modules/@ethersproject/logger/lib/index.js:180:21)
bsc-bot_1  |     at Logger.throwError (/home/node/app/node_modules/@ethersproject/logger/lib/index.js:189:20)
bsc-bot_1  |     at /home/node/app/node_modules/@ethersproject/abstract-signer/lib/index.js:263:47
bsc-bot_1  |     at processTicksAndRejections (internal/process/task_queues.js:97:5)
bsc-bot_1  |     at async Promise.all (index 5) {
bsc-bot_1  |   reason: 'cannot estimate gas; transaction may fail or may require manual gas limit',
bsc-bot_1  |   code: 'UNPREDICTABLE_GAS_LIMIT',
bsc-bot_1  |   error: Error: cannot estimate gas; transaction may fail or may require manual gas limit (error={"code":3,"response":"{\"jsonrpc\":\"2.0\",\"id\":10,\"error\":{\"code\":3,\"data\":\"0x08c379a0000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000000245472616e7366657248656c7065723a205452414e534645525f46524f4d5f4641494c454400000000000000000000000000000000000000000000000000000000\",\"message\":\"execution reverted: TransferHelper: TRANSFER_FROM_FAILED\"}}"}, method="estimateGas", transaction={"from":"0x09F574b25F6Ce593B26fFce3058E005c2c7683E9","gasPrice":{"type":"BigNumber","hex":"0x3b9aca00"},"to":"0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D","data":"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"}, code=UNPREDICTABLE_GAS_LIMIT, version=providers/5.0.24)

[alexreyes]

I never did end up figuring out how to fix the issue. I just pivoted to using Web3.js even though ethers.js was much nicer to use :(

[ricmoo]

Have you tried setting a manual gasLimit? That means the call to estimate gas is failing. It could be because the transaction will fail (e.g. a require(balance > value)), but it could just be the node cant compute it for you (sometimes complex operations confuse it).

Try overriding gasLimit?

[zemse]

While you're trying, I'd also like to suggest including the following line, which may help figure out the problem.

 const erc20_rw = new ethers.Contract(daiAddress, daiAbi, wallet)

  // add this following both lines
  const balance = await erc20_rw.balanceOf(wallet.address);
  console.log('balance: ' + ethers.utils.formatUnits(balance, 18));

  // // Each DAI has 18 decimal places
  const dai = ethers.utils.parseUnits("1.0", 18);

  await erc20_rw.transfer('0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D', dai);
}

let us know if you can successfully see the balance printed.

[hamishjohnson]

Have you tried setting a manual gasLimit? That means the call to estimate gas is failing. It could be because the transaction will fail (e.g. a require(balance > value)), but it could just be the node cant compute it for you (sometimes complex operations confuse it).

Try overriding gasLimit?

how do you manually set gasLimit

[zemse]

await erc20_rw.transfer('0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D', dai, {
  gasLimit: 1000000
});

For more docs you can visit here.

[hamishjohnson]

Overriding the gasLimit worked for me :) tyvm

[ricmoo]

I think @zemse answered the OP, so I’ll close this now, but if I’m mistaken, please re-open.

Thanks! :)