Attempting to deploy this smart contract on the Mumbai Testnet.

The contract deploys and it's address is 0x435daA3ba0d89A92b91174DC745D013c201fcF6a.

But, when I try and press on the accept ownership button, it says that a function inside the smart contract failed to execute. I have tried flattening and everything. Please if someone can help that would be great.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

import {FunctionsClient} from "@chainlink/contracts/src/v0.8/functions/dev/v1_0_0/FunctionsClient.sol";
import {ConfirmedOwner} from "@chainlink/contracts/src/v0.8/shared/access/ConfirmedOwner.sol";
import {FunctionsRequest} from "@chainlink/contracts/src/v0.8/functions/dev/v1_0_0/libraries/FunctionsRequest.sol";

 * @title Chainlink Functions example on-demand consumer contract example
contract rest is FunctionsClient, ConfirmedOwner {
  using FunctionsRequest for FunctionsRequest.Request;

  bytes32 public donId; // DON ID for the Functions DON to which the requests are sent

  bytes32 public s_lastRequestId;
  bytes public s_lastResponse;
  bytes public s_lastError;

  constructor(address router, bytes32 _donId) FunctionsClient(router) ConfirmedOwner(msg.sender) {
    donId = _donId;

   * @notice Set the DON ID
   * @param newDonId New DON ID
  function setDonId(bytes32 newDonId) external onlyOwner {
    donId = newDonId;

   * @notice Triggers an on-demand Functions request using remote encrypted secrets
   * @param source JavaScript source code
   * @param secretsLocation Location of secrets (only Location.Remote & Location.DONHosted are supported)
   * @param encryptedSecretsReference Reference pointing to encrypted secrets
   * @param args String arguments passed into the source code and accessible via the global variable `args`
   * @param bytesArgs Bytes arguments passed into the source code and accessible via the global variable `bytesArgs` as hex strings
   * @param subscriptionId Subscription ID used to pay for request (FunctionsConsumer contract address must first be added to the subscription)
   * @param callbackGasLimit Maximum amount of gas used to call the inherited `handleOracleFulfillment` method
  function sendRequest(
    string calldata source,
    FunctionsRequest.Location secretsLocation,
    bytes calldata encryptedSecretsReference,
    string[] calldata args,
    bytes[] calldata bytesArgs,
    uint64 subscriptionId,
    uint32 callbackGasLimit
  ) external onlyOwner {
    FunctionsRequest.Request memory req; // Struct API reference: https://docs.chain.link/chainlink-functions/api-reference/functions-request
    req.initializeRequest(FunctionsRequest.Location.Inline, FunctionsRequest.CodeLanguage.JavaScript, source);
    req.secretsLocation = secretsLocation;
    req.encryptedSecretsReference = encryptedSecretsReference;
    if (args.length > 0) {
    if (bytesArgs.length > 0) {
    s_lastRequestId = _sendRequest(req.encodeCBOR(), subscriptionId, callbackGasLimit, donId);

   * @notice Store latest result/error
   * @param requestId The request ID, returned by sendRequest()
   * @param response Aggregated response from the user code
   * @param err Aggregated error from the user code or from the execution pipeline
   * Either response or error parameter will be set, but never both
  function fulfillRequest(bytes32 requestId, bytes memory response, bytes memory err) internal override {
    s_lastResponse = response;
    s_lastError = err;

1 Answer 1


Because the address is the owner itself or not the pending_address to take ownership of the contract.

There are 2 steps to transfer the ownership of the contract.

  1. Current owner call function transferOwnership(newOwner).
  2. New owner call function acceptOwnership() to get the ownership.

It looks like you miss the first step.

In your contract, ConfirmedOwner.sol is imported to your contract through the line so the related functions are defined there.

If you check the function acceptOwnership() in contract ConfirmedOwnerWithProposal, it can be found that address who calls the message has to be s_pendingOwner.

The way to assign a new address to s_pendingOwner is to call the function transferOwnership(address to) which is also defined in the same contract.

  • The problem is that even when I do that, I still get the following message: '0x0 Transaction mined but execution failed' The contract address is now: 0x2F2928D64a0d617Db3d3a778aCbe205B25cc20D3 I can't even verify the contract for some reason
    – kixsmart
    Nov 20, 2023 at 22:06
  • @kixsmart , I cannot reproduce your issue, please test it on remix with virtual machine and you don't need to verify the contract.
    – Frank Kong
    Nov 21, 2023 at 6:37

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.