Why am I receiving the following Chainlink error: cannot estimate gas - blockchain

Question

I am trying to follow the Chainlink VRF tutorial found here: https://docs.chain.link/docs/intermediates-tutorial/ with hardhat and am running into this issue when calling the rollDice function:
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":"0x014Da1D627E6ceB555975F09D26B048644382Ac6","maxPriorityFeePerGas":{"type":"BigNumber","hex":"0x9502f900"},"maxFeePerGas":{"type":"BigNumber","hex":"0x9502f90e"},"to":"0x5887946875A01D1BB79d6Fb357BceeA5A0096D2e","data":"0xdd02d9e5000000000000000000000000014da1d627e6ceb555975f09d26b048644382ac6","type":2,"accessList":null}}, tx={"data":"0xdd02d9e5000000000000000000000000014da1d627e6ceb555975f09d26b048644382ac6","to":{},"from":"0x014Da1D627E6ceB555975F09D26B048644382Ac6","type":2,"maxFeePerGas":{"type":"BigNumber","hex":"0x9502f90e"},"maxPriorityFeePerGas":{"type":"BigNumber","hex":"0x9502f900"},"nonce":{},"gasLimit":{},"chainId":{}}, code=UNPREDICTABLE_GAS_LIMIT, version=abstract-signer/5.5.0)
at Logger.makeError (/Users/matt/Desktop/hardhat/randomDay/node_modules/#ethersproject/logger/src.ts/index.ts:225:28)
at Logger.throwError (/Users/matt/Desktop/hardhat/randomDay/node_modules/#ethersproject/logger/src.ts/index.ts:237:20)
at /Users/matt/Desktop/hardhat/randomDay/node_modules/#ethersproject/abstract-signer/src.ts/index.ts:301:31
at processTicksAndRejections (node:internal/process/task_queues:96:5)
at async Promise.all (index 7)
I am able to deploy to the Kovan testnet, I was able to verify the contract, and I have sent the contract LINK tokens, but am still running into the issue. The contract can be viewed here: https://kovan.etherscan.io/address/0x7b72d80670512c87605ab8ac7e6113fda9c57de4#code
I am using version 0.8 of the Chainlink Contracts.
RandomDay.sol
pragma solidity ^0.8.9;
import "#chainlink/contracts/src/v0.8/VRFConsumerBase.sol";
contract RandomDay is VRFConsumerBase {
uint256 private constant ROLL_IN_PROGRESS = 42;
bytes32 private s_keyHash;
uint256 private s_fee;
mapping(bytes32 => address) private s_rollers;
mapping(address => uint256) private s_results;
event DiceRolled(bytes32 indexed requestId, address indexed roller);
event DiceLanded(bytes32 indexed requestId, uint256 indexed result);
constructor(address vrfCoordinator, address link, bytes32 keyHash, uint256 fee) VRFConsumerBase(vrfCoordinator, link) {
s_keyHash = keyHash;
s_fee = fee;
}
function rollDice (address roller) public returns (bytes32 requestId) {
require(LINK.balanceOf(address(this)) >= s_fee, "Not enough LINK to pay fee");
require(s_results[roller] == 0, "Already rolled");
requestId = requestRandomness(s_keyHash, s_fee);
s_rollers[requestId] = roller;
s_results[roller] = ROLL_IN_PROGRESS;
emit DiceRolled(requestId, roller);
return requestId;
}
function fulfillRandomness (bytes32 requestId, uint256 randomness) internal override {
uint256 dayOfWeek = (randomness % 7) + 1;
s_results[s_rollers[requestId]] = dayOfWeek;
emit DiceLanded(requestId, dayOfWeek);
}
function weekday (address player) public view returns (string memory) {
require(s_results[player] != 0, "Dice not rolled");
require(s_results[player] != ROLL_IN_PROGRESS, "Roll in progress");
return getWeekdayName(s_results[player]);
}
function getWeekdayName (uint256 id) private pure returns (string memory) {
string[7] memory weekdays = [ "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"];
return weekdays[id - 1];
}
}
hardhat.config.js
/**
* #type import('hardhat/config').HardhatUserConfig
*/
require("#nomiclabs/hardhat-waffle")
require("#nomiclabs/hardhat-etherscan")
const ALCHEMY_API_KEY = "*************************";
const ROPSTEN_PRIVATE_KEY = "*********************";
module.exports = {
solidity: "0.8.9",
networks: {
kovan: {
url: `https://eth-kovan.alchemyapi.io/v2/${ALCHEMY_API_KEY}`,
accounts: [`0x${ROPSTEN_PRIVATE_KEY}`],
gas: 2700000000,
maxFeePerGas: 30000000000,
}
},
etherscan: {
// Your API key for Etherscan
// Obtain one at https://etherscan.io/
apiKey: "****************************"
}
};
deploy.js
const { ethers } = require("hardhat");
async function main() {
const [deployer] = await ethers.getSigners();
console.log("Deploying contracts with the account:", deployer.address);
console.log("Account balance:", (await deployer.getBalance()).toString());
const Token = await ethers.getContractFactory("RandomDay");
const token = await Token.deploy("0xa36085F69e2889c224210F603D836748e7dC0088", "0xdD3782915140c8f3b190B5D67eAc6dc5760C46E9", "0x6c3699283bda56ad74f6b855546325b68d482e983852a7a82979cc4807b641f4", "100000000000000000");
console.log("Token address:", token.address);
}
main()
.then(() => process.exit(0))
.catch((error) => {
console.error(error);
process.exit(1);
});
quickRun.js
var ethers = require('ethers');
var provider = ethers.providers.getDefaultProvider('kovan');
var address = '0x7b72d80670512c87605aB8aC7E6113Fda9c57de4';
var abi = [{"inputs":[{"internalType":"address","name":"vrfCoordinator","type":"address"},{"internalType":"address","name":"link","type":"address"},{"internalType":"bytes32","name":"keyHash","type":"bytes32"},{"internalType":"uint256","name":"fee","type":"uint256"}],"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"requestId","type":"bytes32"},{"indexed":true,"internalType":"uint256","name":"result","type":"uint256"}],"name":"DiceLanded","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"requestId","type":"bytes32"},{"indexed":true,"internalType":"address","name":"roller","type":"address"}],"name":"DiceRolled","type":"event"},{"inputs":[{"internalType":"bytes32","name":"requestId","type":"bytes32"},{"internalType":"uint256","name":"randomness","type":"uint256"}],"name":"rawFulfillRandomness","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"roller","type":"address"}],"name":"rollDice","outputs":[{"internalType":"bytes32","name":"requestId","type":"bytes32"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"player","type":"address"}],"name":"weekday","outputs":[{"internalType":"string","name":"","type":"string"}],"stateMutability":"view","type":"function"}];
var privateKey = '*******************************';
var wallet = new ethers.Wallet(privateKey, provider);
var contract = new ethers.Contract(address, abi, wallet);
var sendPromise = contract.rollDice('0x014Da1D627E6ceB555975F09D26B048644382Ac6');
sendPromise.then(function(transaction){
console.log(transaction);
});

Answer 1

I believe the addresses are off:
Constructor Arguments of your contract:
-----Decoded View---------------
Arg [0] : vrfCoordinator (address): 0xa36085f69e2889c224210f603d836748e7dc0088
Arg [1] : link (address): 0xdd3782915140c8f3b190b5d67eac6dc5760c46e9
Arg [2] : keyHash (bytes32): 0x6c3699283bda56ad74f6b855546325b68d482e983852a7a82979cc4807b641f4
Arg [3] : fee (uint256): 100000000000000000
Via Chainlinks Docs:
LINK 0xa36085F69e2889c224210F603D836748e7dC0088
VRF Coordinator 0xdD3782915140c8f3b190B5D67eAc6dc5760C46E9
Key Hash 0x6c3699283bda56ad74f6b855546325b68d482e983852a7a82979cc4807b641f4
Fee 0.1 LINK
Switched Link and VRF are probably the culprit.

Answer 2

9 out of 10 is because you passed something wrong in the constructor or something in the contructor is not initialized propertly. this kind of things aren't detected by compiler.