Uniswap swapRouter02 Error: Transaction reverted without a reason string - ethereum

Question

I'm testing uniswap's swap transaction
my new contract swap() -> uniswap swapRouter02 contract exactInputSingle() which is not from wallet to contract swap
Specifically below code is trying swap my contract's 0.08 WETH to some UNI. and I checked my contract has 0.08 weth.
0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2 => WETH token address
0x1f9840a85d5aF5bf1D1762F925BDADdC4201F984 => UNI token address
0x68b3465833fb72A70ecDF485E0e4C7bD8665Fc45 => Uniswap SwapRouter02 contract address
but error message when try
ISwapRouter02(0x68b3465833fb72A70ecDF485E0e4C7bD8665Fc45).exactInputSingle(params);
Error: Transaction reverted without a reason string at ~~
what does this message mean? and how can I debug this error?
My test environment is hardhat local forking mainnet. The error message is from hardhat forking mainnet
hardhat: {
chainId: 31337,
forking: {
url: `https://mainnet.infura.io/v3/${INFURA_API_KEY}`,
blockNumber: 14390000
},
},
function swap() external payable override lock returns (uint256) {
//approve
address(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2).call(abi.encodeWithSelector(IERC20.approve.selector, 0x68b3465833fb72A70ecDF485E0e4C7bD8665Fc45, 0x011C37937E080000));
//test
uint256 amountOut;
ISwapRouter02.ExactInputSingleParams memory params =
IV3SwapRouter.ExactInputSingleParams({
tokenIn: 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2,
tokenOut: 0x1f9840a85d5aF5bf1D1762F925BDADdC4201F984,
fee: 0,
recipient: msg.sender,
//deadline: _params.deadline,
amountIn: 0x011C37937E080000, //0.08
amountOutMinimum: 0x0,
sqrtPriceLimitX96: 0
});
ISwapRouter02(0x68b3465833fb72A70ecDF485E0e4C7bD8665Fc45).exactInputSingle(params);
return 1;
}
Error: cannot estimate gas; transaction may fail or may require manual gas limit [ See: https://links.ethers.org/v5-errors-UNPREDICTABLE_GAS_LIMIT ] (reason="Error: Transaction reverted without a reason string", method="estimateGas", transaction={"from":"0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266","to":"0xd5a946A0C214d732a8cf5678be593d26E1bf2170","data":"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","accessList":null}, error={"name":"ProviderError","code":-32603,"_isProviderError":true,"data":{"message":"Error: Transaction reverted without a reason string","data":"0x"}}, code=UNPREDICTABLE_GAS_LIMIT, version=providers/5.6.8)

Answer 1

I found my fault,
reason was amountOutMinimum value must be not 0x0