Troubleshooting Errors

Error Codes

In order to reduce gas usage and code size, aave contracts return numbered errors. If you are making calls to the protocol and receive numbered errors, you can use the reference below to know what is the error. Alternatively, you can also find what the numbers represent by checking the Errors.sol

Reference Guide

ValidationLogic and LendingPoolCollateralManager return some collateral related errors. Return type uint

ERROR CODE (uint)	ERROR DESCRIPTION
0	No Error
1	No Collateral available
2	Collateral cannot be liquidated
3	Currency not borrowed
4	Health factor above threshold
5	Not enough liquidity
6	Health factor lower than liquidation threshold
7	Invalid equal assets to swap
8	Frozen reserve

Other error codes returned as string:

ERROR CODE (string)	ORIGINATOR	ERROR DESCRIPTION
1	ValidationLogic	Amount must be greater than 0
2	ValidationLogic	Action requires an active reserve
3	ValidationLogic	Action cannot be performed because the reserve is frozen
4	ValidationLogic	The current liquidity is not enough
5	ValidationLogic	User cannot withdraw more than the available balance
6	ValidationLogic	Transfer cannot be allowed
7	ValidationLogic	Borrowing is not enabled
8	ValidationLogic	Invalid interest rate mode selected
9	ValidationLogic	Collateral balance is 0
10	ValidationLogic	Health factor is lesser than the liquidation threshold
11	ValidationLogic	There is not enough collateral to cover a new borrow
12	ValidationLogic	Stable borrowing not enabled
13	ValidationLogic	Collateral is same currency that is being borrowed
14	ValidationLogic	The requested amount is greater than the max loan size in stable rate mode
15	ValidationLogic	No debt of selected type
16	ValidationLogic	To repay on behalf of a user an explicit amount to repay is needed
17	ValidationLogic	User does not have a stable rate loan in this reserve
18	ValidationLogic	User does not have a variable rate loan in this reserve
19	ValidationLogic	Underlying balance needs to be greater than 0
20	ValidationLogic	User deposit is already being used as collatoral
21	LendingPool	Not enough stable rate borrow balance
22	LendingPool	Interest rate rebalance conditions not met
23	LendingPool	Liquidation call failed
24	LendingPool	Not enough liquidity to borrow
25	LendingPool	Requested amount too small for flashloan
26	LendingPool	The actual balance of protocol is inconsistent
27	LendingPool	The caller of the function is not lending pool configurator
28	LendingPool	Inconsistent flashloan params
29	a/Debt Token	Caller must be lending pool
30	a/Debt Token	User cannot give allowance to oneself
31	a/Debt Token	Transfer amount needs to be > 0
32	ReserveLogic	Reserve has already been initialised
33		Caller not pool admin
34	LendingPoolConfigurator	Liquidity of reserve needs to be 0
35	LendingPoolConfigurator	Invalid aToken pool address
36	LendingPoolConfigurator	Invalid stable debt token pool address
37	LendingPoolConfigurator	Invalid variable debt token pool address
38	LendingPoolConfigurator	Invalid address of underlying asset for stabled debt token
39	LendingPoolConfigurator	Invalid address of underlying asset for variable debt token
40	LendingPoolConfigurator	Invalid address provider id
41	LendingPoolAddressesProviderRegistry	Provider is not registered
42	LendingPoolCollateralManager	Health factor not below threshold
43	LendingPoolCollateralManager	Collateral cannot be liquidated
44	LendingPoolCollateralManager	User did not borrow the specified currency
45	LendingPoolCollateralManager	Not enough liquidity to liquidate
46	LendingPoolCollateralManager	No errors
47	LiquidityProvider	Invalid flashloan mode
48	Math	Multiplication overflow
49	Math	Addition overflow
50	Math	Division by zero
51	ReserveLogic	Liquidity index overflows
52	ReserveLogic	Variable borrow index overflow
53	ReserveLogic	Liquidity rate overflow
54	ReserveLogic	Variable borrow rate overflow
55	ReserveLogic	Stable borrow rate overflow
56	a/Debt Token	Invalid mint amount
57	LendingPool	Failed to repay with collateral
58	a/Debt Token	Invalid burn amount
59		Borrow allowance not enough
60	LendingPool	Failded collateral swap
61	LendingPool	Invalid equal assets to swap
62	LendingPool	Reentrancy not allowed
63	LendingPool	Caller must be an aToken
64	LendingPool	Pool is paused
65	LendingPool	No more reserves allowed
66	LendingPool	Invalid amount returned from flash loan executor
67	ReserveConfiguration	Invalid locked total value
68	ReserveConfiguration	Invalid liquidity threshold
69	ReserveConfiguration	Invalid liquidity bonus
70	ReserveConfiguration	Invalid decimals
71	ReserveConfiguration	Invalid reserve factor
72	LendingPoolAddressesProviderRegistry	Invalid address provider id
73	ValidationLogic	Inconsistent flashloan params
74	LendingPool	Inconsistent params length
75	LendingPoolConfigurator	Invalid configuration
76	LendingPoolConfigurator	Caller is not an emergency admin
77	UserConfiguration	Invalid index
78	LendingPool	Not a contract
79	stableDebtToken	Stable debt overflow
80	stableDebtToken	Burn exceeds balance

Debugging transactions on mainnet / Kovan

If your contracts are successfully deployed on a public network, then you can use the very useful service Tenderly.

Tenderly allows you to debug transactions, just like you would on a local instance, using their powerful tools. If your transaction has reverted, try using their debugger to find the line of code where your transaction failed.

Debugging transactions in Truffle

If you have an instance of Truffle running (e.g. console or develop), then you can debug specific transactions using debug YOUR_TX_HASH into your Truffle instance. For more information, see the ez-flashloan starter template README.MD.

EVM revert SafeERC20: low-level call failed

This error indicates that a call to the SafeERC20 implementation of a function has failed. In production, you want to keep using these SafeERC20 implementations.

However in testing, you may want more precise EVM error messages by removing the SafeERC20 implementations. You can do this by replacing the SafeERC20 calls with standard ERC20 calls. For example, in the ez-flashloan starter template, replace the following:

IERC20(_reserve).safeTransfer(_destination, _amount);

with:

IERC20(_reserve).transfer(_destination, _amount);

You will then receive standard EVM error messages if it reverts on this line, which can sometimes be more helpful for debugging purposes.

Web3 error: nonce too low

This error is usually due to the nonce that is being used by your web3 wallet, when creating a transaction to send. It means that the nonce being used is not correct, as the Ethereum node your wallet is communicating with indicates that there is a more recent transaction (with a higher nonce). Here is a good overview of nonces in Ethereum transactions.

Some potential solutions:

• If using a web3 wallet such as MetaMask: Go to your MetaMask settings --> Advanced --> Reset Account. This will reset the transaction history stored in your local browser cache, including the nonce count. The next transaction you send will use the most recent nonce from the Ethereum node your wallet is connected to.

• If the error is not coming from your web3 wallet, then it may be due to the Ethereum node it is connected to. For services such as Infura, their network consist of many servers, where a previously submitted transaction may not be present on the server you are currently connected to. In these cases, wait a few minutes, then try again.