从 Aave 提款会导致“错误交易已恢复”

我正在运行一个示例，它将 Aave 代币存入 Aave 中。我正在使用提供的代码合同示例Aave v2 github https://github.com/aave/code-examples-protocol/tree/main/V2/Credit%20Delegation

// Fork Kovan
await hre.network.provider.request({
    method: 'hardhat_reset',
    params: [{ forking: { jsonRpcUrl: KOVAN_JSON_RPC } }],
});

// Act like AAVE_HOLDER
await hre.network.provider.request({
    method: 'hardhat_impersonateAccount',
    params: [AAVE_HOLDER],
});
const signer = await hre.ethers.getSigner(AAVE_HOLDER);
console.log('signer:', signer.address);

// AAVE token on Kovan network
const aavetoken = IERC20__factory.connect(AAVE_TOKEN_ADDRESS, signer);
console.log('token balance:', (await aavetoken.balanceOf(signer.address)).toString());

const MyV2CreditDelegation = new MyV2CreditDelegation__factory(signer);
const delegation = await MyV2CreditDelegation.deploy({ gasLimit: 1e7 });
console.log('delegation:', delegation.address);

// Set the allowance higher than the deposit amount
// so we know we can make multiple transactions
let allowance = 100000
let despositAmount = 10;

await aavetoken.approve(delegation.address, allowance);
console.log('allowance:', (await aavetoken.allowance(signer.address, delegation.address, { gasLimit: 1e6 })).toString());

const depositTrans = await delegation.depositCollateral(aavetoken.address, despositAmount, true, { gasLimit: 1e6 });
console.log('depositTrans:', depositTrans.hash);
const depositReceipt = await depositTrans.wait();

存款工作正常，但是当我尝试取款时：

try  {
    var withdrawTrans = await delegation
        .withdrawCollateral(aavetoken.address,  { gasLimit: 1e6 })

    console.log('withdrawTrans:', withdrawTrans.hash);
    const withdrawReceipt = await withdrawTrans.wait();
}
catch (err) {
    console.log('Error:' + err);
}

我收到错误：

事务已恢复：函数返回了意外数量的数据

我对安全帽还很陌生，我现在知道如何进一步调试它。 我如何从 Aave 提款？