# Troubleshooting (v4) (/docs/protocols/v4/guides/troubleshooting)

Review common Uniswap v4 custom error selectors to debug integration and runtime failures.

These are custom error selectors for Uniswap v4 contracts.

## Core Manager and Hook Selectors
## IPoolManager.sol
| Error Selector                                         | Hex Value    |
| ------------------------------------------------------ | ------------ |
| `IPoolManager.CurrencyNotSettled.selector`             | `0x5212cba1` |
| `IPoolManager.PoolNotInitialized.selector`             | `0x486aa307` |
| `IPoolManager.AlreadyUnlocked.selector`                | `0x5090d6c6` |
| `IPoolManager.ManagerLocked.selector`                  | `0x54e3ca0d` |
| `IPoolManager.TickSpacingTooLarge.selector`            | `0xb02b5dc2` |
| `IPoolManager.TickSpacingTooSmall.selector`            | `0x16fe7696` |
| `IPoolManager.CurrenciesOutOfOrderOrEqual.selector`    | `0xeaa6c6eb` |
| `IPoolManager.UnauthorizedDynamicLPFeeUpdate.selector` | `0x30d21641` |
| `IPoolManager.SwapAmountCannotBeZero.selector`         | `0xbe8b8507` |
| `IPoolManager.NonZeroNativeValue.selector`             | `0x19d245cf` |

## Hooks.sol
| Error Selector                              | Hex Value    |
| ------------------------------------------- | ------------ |
| `Hooks.HookAddressNotValid.selector`        | `0xe65af6a0` |
| `Hooks.InvalidHookResponse.selector`        | `0x1e048e1d` |
| `Hooks.FailedHookCall.selector`             | `0x36bc48c5` |
| `Hooks.HookDeltaExceedsSwapAmount.selector` | `0xfa0b71d6` |

## Pool.sol
| Error Selector                            | Hex Value    |
| ----------------------------------------- | ------------ |
| `Pool.TicksMisordered.selector`           | `0xc4433ed5` |
| `Pool.TickLowerOutOfBounds.selector`      | `0xd5e2f7ab` |
| `Pool.TickUpperOutOfBounds.selector`      | `0x1ad777f8` |
| `Pool.TickLiquidityOverflow.selector`     | `0xb8e3c385` |
| `Pool.TickNotInitialized.selector`        | `0x82a774d3` |
| `Pool.PoolAlreadyInitialized.selector`    | `0x7983c051` |
| `Pool.PoolNotInitialized.selector`        | `0x486aa307` |
| `Pool.PriceLimitAlreadyExceeded.selector` | `0x7c9c6e8f` |
| `Pool.PriceLimitOutOfBounds.selector`     | `0x9e4d7cc7` |
| `Pool.NoLiquidityToReceiveFees.selector`  | `0xa74f97ab` |
| `Pool.InvalidFeeForExactOut.selector`     | `0x96206246` |

## Fee, Position, and Reserve Selectors
## IProtocolFees.sol
| Error Selector                                      | Hex Value    |
| --------------------------------------------------- | ------------ |
| `IProtocolFees.ProtocolFeeCannotBeFetched.selector` | `0x1ee49702` |
| `IProtocolFees.InvalidProtocolFee.selector`         | `0xba97f838` |
| `IProtocolFees.InvalidCaller.selector`              | `0x48f5c3ed` |

## LPFeeLibrary.sol
| Error Selector                      | Hex Value    |
| ----------------------------------- | ------------ |
| `LPFeeLibrary.FeeTooLarge.selector` | `0xfc5bee12` |

## Position.sol
| Error Selector                                | Hex Value    |
| --------------------------------------------- | ------------ |
| `Position.CannotUpdateEmptyPosition.selector` | `0xaefeb924` |

## Reserves.sol
| Error Selector                           | Hex Value    |
| ---------------------------------------- | ------------ |
| `Reserves.ReservesMustBeSynced.selector` | `0x8774be48` |

## Math and Tick Selectors
## SqrtPriceMath.sol
| Error Selector                                   | Hex Value    |
| ------------------------------------------------ | ------------ |
| `SqrtPriceMath.InvalidPriceOrLiquidity.selector` | `0x4f2461b8` |
| `SqrtPriceMath.InvalidPrice.selector`            | `0x00bfc921` |
| `SqrtPriceMath.NotEnoughLiquidity.selector`      | `0x4323a555` |
| `SqrtPriceMath.PriceOverflow.selector`           | `0xf5c787f1` |

## TickBitmap.sol
| Error Selector                       | Hex Value    |
| ------------------------------------ | ------------ |
| `TickBitmap.TickMisaligned.selector` | `0xd4d8f3e6` |

## TickMath.sol
| Error Selector                       | Hex Value    |
| ------------------------------------ | ------------ |
| `TickMath.InvalidTick.selector`      | `0xce8ef7fc` |
| `TickMath.InvalidSqrtPrice.selector` | `0x31efafe8` |