Task #2: Customer Support

Technical troubleshooting guide: "Why doesn't my 2 USDC deposit go through?"

Customer Issue

A customer is trying to deposit 2 USDC into a Kiln DeFi vault but the transaction is failing. They need our help to understand why and how to fix it.

Step 1: Confirming the Vault & Amount

1. Vault Address Check

Extract to = 0x4b2A436B544E276783042750D6678dC30368EF35

Call Kiln DeFi Reporting API:

GET https://api.mainnet.kiln.fi/v1/defi/vaults?chainId=8453

→ Find a vault whose contractAddress matches exactly ⇒ confirms it's the Kiln × Morpho Base vault.

2. Amount Decode

Calldata method ID:

0x6e553f65 = deposit(uint256)

Argument hex to decimal:

0x…01eb480 → decimal 2,000,000

USDC has 6 decimals:

2,000,000 units = 2 USDC
Confirms deposit of 2 USDC

Step 2: Debugging the Failure by Simulating the Call

1. Simulate via eth_call

const result = await provider.call({
  to: vaultAddress,
  data: rawTx.data,
  from: rawTx.from
});

2. Expected Error Response

Error: VM Exception while processing transaction: revert ERC20: transfer amount exceeds allowance

3. Root Cause Analysis

Missing ERC-20 allowance

  • • deposit() internally calls usdc.transferFrom(user, vault, amount)
  • • If the vault has no allowance to spend USDC, it reverts
  • • User must approve the vault before depositing

Step 3: Resolution Steps for Customer

1. Approve the vault to spend USDC

await usdcContract.connect(userSigner).approve(
  vaultAddress,
  ethers.utils.parseUnits("2", 6)
);

2. Resubmit the deposit transaction

Once approved, the customer can resubmit the same deposit(2 USDC) transaction.

3. (Optional) Verify on-chain

const allowance = await usdcContract.allowance(user, vaultAddress);
console.log("USDC allowance:", allowance.toString());

Should now be ≥ 2,000,000 (representing 2 USDC with 6 decimals)

Resolution Complete

Customer should now be able to successfully deposit 2 USDC into the Kiln DeFi vault.

Support Methodology Summary

Investigate

Verify vault and decode transaction data

Simulate

Use eth_call to reproduce the error

Resolve

Provide clear fix and verification steps

Ready for data-driven insights?

Next up: Validator performance analysis using real Kiln API data

Continue to Task 3