Troubleshooting Errors

Common error messages. Use the sidebar ➡️to jump to the error you're seeing.


Sometimes you may find yourself facing a problem that doesn't have a clear solution. These troubleshooting tips may help you solve problems you run into.


Issues on the Exchange

INSUFFICIENT_OUTPUT_AMOUNT

The transaction cannot succeed due to error: HOW Router: INSUFFICIENT_OUTPUT_AMOUNT. This is probably an issue with one of the tokens you are swapping.

the transaction cannot succeed due to error: execution reverted: HOW Router: insufficient_output_amount.

You're trying to swap tokens, but your slippage tolerance is too low or liquidity is too low.

INSUFFICIENT_A_AMOUNT or INSUFFICIENT_B_AMOUNT

Fail with error 'HOW Router: INSUFFICIENT_A_AMOUNT'

or

Fail with error 'HOW Router: INSUFFICIENT_B_AMOUNT'

You're trying to add/remove liquidity from a liquidity pool (LP), but there isn't enough of one of the two tokens in the pair.

HOW Router: EXPIRED

The transaction cannot succeed due to error: HOW Router: EXPIRED. This is probably an issue with one of the tokens you are swapping.

Try again, but confirm (sign and broadcast) the transaction as soon as you generate it.

This happened because you started making a transaction, but you didn't sign and broadcast it until it was past the deadline. That means you didn't hit "Confirm" quickly enough.

Howswap: K

The transaction cannot succeed due to error: HOW: K. This is probably an issue with one of the tokens you are swapping.

Refresh the page and try again, or increase slippage tolerance via the settings icon and try again.

This probably happened because you're trying to buy or sell tokens during a big price movement. The frontend is getting outdated information (e.g. outAmount) from the smart contract, causing the swap to fail.

Howswap: TRANSFER_FAILED

The transaction cannot succeed due to error: execution reverted: HOW: TRANSFER_FAILED.

Make sure you have 30% more tokens in your wallet than you intend to trade, or try to trade a lower amount. If you want to sell the maximum possible, try 70% or 69% instead of 100%. Caused by the design of Restorative Rebase tokens like tDoge or tBTC. Understand how restorative rebase tokens work.

Transaction cannot succeed

Try trading a smaller amount, or increase slippage tolerance via the settings icon and try again. This is caused by low liquidity.

Price Impact too High

Try trading a smaller amount, or increase slippage tolerance via the settings icon and try again. This is caused by low liquidity.

estimateGas failed

This transaction would fail. Please contact support

Cannot read property 'to Hex String' of undefined

Unknown error: "Cannot read property 'toHexString' of undefined

When trying to swap tokens, the transaction fails and this error message is displayed. This error has been reported on mobile devices using Trust Wallet.

Execution reverted: TransferHelper: TRANSFER_FROM_FAILED.

The transaction cannot succeed due to error: execution reverted: TransferHelper: TRANSFER_FROM_FAILED.

When trying to swap tokens, the transaction fails and this error message is displayed. This error has been reported across platforms.

Issues with Syrup Pools

BEP20: burn amount exceeds balance

Fail with error 'BEP20: burn amount exceeds balance'

You don't have enough SYRUP in your wallet to unstake from the HOW-HOW pool.

Out of Gas error

Warning! Error encountered during contract execution [out of gas]

You have set a low gas limit when trying to make a transaction.

BEP20: transfer amount exceeds allowance

Fail with error 'BEP20: transfer amount exceeds allowance'

BEP20: transfer amount exceeds balance

Fail with error 'BEP20: transfer amount exceeds balance'

You're probably trying to unstake from a Syrup Pool with low rewards in it. Solution below.

If not, you may be trying to send tokens that you don't have in your wallet (for HOW, trying to send a token that is already assigned to a pending transaction). In this case, just make sure you have the tokens you're trying to use.

Other issues

Provider Error


Provider Error

No provider was found

This happens when you try to connect via a browser extension like MetaMask or Binance Chain Wallet, but you haven’t installed the extension.

Unsupported Chain ID

Switch your chain to Binance Smart Chain. Check your wallet's documentation for a guide if you need help.

Issues buying SAFEMOON and similar tokens

To trade SAFEMOON, you must click on the settings icon and set your slippage tolerance to 12% or more.

This is because SafeMoon taxes a 10% fee on each transaction:

5% fee = redistributed to all existing holders

5% fee = used to add liquidity

This is also why you might not receive as much of the token as you expect when you purchase.

Read more on How to Buy Safe Moon.

Internal JSON-RPC errors

MetaMask - RPC Error: Internal JSON-RPC error. estimateGas failed removeLiquidityETHWithPermitSupportingFeeOnTransferTokens estimateGas failed removeLiquidityETHWithPermit

Happens when trying to remove liquidity on some tokens via Metamask. Root cause is still unknown. Try using an alternative wallet.

Internal JSON-RPC error. { "code": -32000, "message": "insufficient funds for transfer" } - Please try again.

You don't have enough BNB to pay for the transaction fees. You need more BEP-20 network BNB in your wallet.

Error: [ethjs-query]

Error: [ethjs-query] while formatting outputs from RPC '{"value":{"code":-32603,"data":{"code":-32000,"message":"transaction underpriced"}}}"

Increase the gas limit for the transaction in your wallet. Check your wallet's documentation to learn how to increase gas limit.

Swap failed: Error: [ethjs-query] while formatting outputs from RPC '{"value":{"code":-32603,"data":{"code":-32603,"message":"handle request error"}}}'

Cause unclear. Try these steps before trying again:

Increase gas limit

Increase slippage

Clear cache