# Troubleshooting (v3) (/docs/protocols/v3/guides/troubleshooting)

Review common Uniswap v3 integration error codes and what each selector indicates during failures.

Use this reference to map common Uniswap v3 error codes to likely failure causes.

## Math and Oracle Errors
## LiquidityMath.sol
* `LS`: Liquidity Sub
* `LA`: Liquidity Add

## Oracle.sol
* `OLD`: The target must be chronologically after the oldest observation
* `I`: The pool has not been initialized

## Position and Tick Errors
## Position.sol
* `NP`: Burn cannot be called for a position with 0 liquidity

## Tick.sol
* `LO`: LiquidityGrossAfter must be less than MaxLiquidity

## TickMath.sol
* `T`: The given tick must be less than, or equal to, the maximum tick
* `R`: Second inequality must be `<` because the price can never reach the price at the max tick

## Transfer Helper Errors
## TransferHelper.sol
* `TF`: Transfer failed

## Pool Errors
## UniswapV3Pool.sol
* `LOK`: Reentrancy guard. A transaction cannot re-enter the pool mid-swap
* `TLU`: The lower tick must be below the upper tick
* `TLM`: The lower tick must be greater than, or equal to, the minimum tick
* `TUM`: The upper tick must be less than, or equal to, the maximum tick
* `AI`: The pool is already initialized
* `M0`: Mint 0. Token0 balance before minting must be less than, or equal to, the balance after minting
* `M1`: Mint 1. Token1 balance before minting must be less than, or equal to, the balance after minting
* `AS`: `amountSpecified` cannot be zero
* `SPL`: Square root price limit
* `IIA`: Insufficient input amount. An insufficient amount of input token was sent during the callback
* `L`: Liquidity in the pool must be greater than zero for a flash to execute
* `F0`: Token0 balance before flash must be less than, or equal to, token0 balance after flash plus fee
* `F1`: Token1 balance before flash must be less than, or equal to, token1 balance after flash plus fee