Troubleshooting Errors

Issues on the Exchange

INSUFFICIENT_OUTPUT_AMOUNT

The transaction cannot succeed due to error: CSTRouter: 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: CSTRouter: insufficient_output_amount.

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

Solution(s)

• Refresh your page and try again later.

• Try trading a smaller amount.

• Increase your slippage tolerance:

  1. Tap the settings icon on the liquidity page;

  2. Increase your slippage tolerance a little;

  3. Try running the transaction again.

• Lastly, try inputting an amount with fewer decimal places.

Explanation

This usually happens when trading tokens with low liquidity.

That means there isn't enough of one of the tokens you're trying to swap in the Liquidity Pool: it's probably a small-cap token that few people are trading.

However, there's also the chance that you're trying to trade a scam token which cannot be sold. In this case, CryptoSwap isn't able to block a token or return funds.

INSUFFICIENT_A_AMOUNT or INSUFFICIENT_B_AMOUNT

Fail with error 'CSTRouter: INSUFFICIENT_A_AMOUNT' or Fail with error 'CSTRouter: INSUFFICIENT_B_AMOUNT'

Solution(s)

• Refresh your page and try again later.

• Increase your slippage tolerance:

  1. Tap the settings icon on the liquidity page;

  2. Increase your slippage tolerance a little;

  3. Try running the transaction again.

Explanation

The error is caused by trying to add or remove liquidity for a liquidity pool (LP) with an insufficient amount of token A or token B (one of the tokens in the pair).

It might be the case that prices are updating too fast when and your slippage tolerance is too low.

CSTRouter: EXPIRED

The transaction cannot succeed due to error: CSTRouter: 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.

Solution(s)

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

Explanation

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.

CSTRouter: K

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

Solution(s)

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

Explanation

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.

CST: TRANSFER_FAILED

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

Solution(s)

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%.

Explanation

Caused by the design of Restorative Rebase tokens like tDoge or tBTC. Understand how restorative rebase tokens work.

Transaction cannot succeed

or

Price impact too high

Solution(s)

Try trading a smaller amount, or increase slippage tolerance via the settings icon and try again.

Explanation

Caused by low liquidity.

estimateGas failed

This transaction would fail. Please contact support

Solution(s)

1. Attempt the transaction again with increased slippage allowance;

2. Consider using another wallet (such as SafePal) for your transaction.

Explanation

This usually happens when trading tokens with insufficient slippage allowance on Trust Wallet.

The exact details of the problem are still being investigated.

Cannot read property 'toHexString' 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.

Solution(s)

1. Attempt the transaction again with increased slippage allowance;

2. Consider using another wallet (such as SafePal) for your transaction.

Explanation

This usually happens when trading tokens with insufficient slippage allowance on Trust Wallet.

The exact details of the problem are still being investigated.

Execution reverted: TransferHelper: TRANSFER_FROM_FAILED

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

Solution(s)

Check to make sure you have sufficient funds available.

Ensure you have given the contract allowance to spend the amount of funds you're attempting to trade with.

Explanation

This error happens when trading tokens with insufficient allowance, or when a wallet has insufficient funds.

If you're trading tokens with Restorative Rebase like tau assets tDoge or tBTC, make sure you understand how they work first with this guide to Rebase tokens.

Issues with Pools

Out of Gas error

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

Solution(s)

Try manually increasing the gas limit (not gas price!) in your wallet before signing the transaction.

A limit of 200000 is usually enough.

The above example is from Metamask; check your wallet's documentation if you aren't sure how to adjust the gas limit.

Explanation

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

Basically, your wallet (Metamask, Trust Wallet, etc.) can't finish what it's trying to do.

Your wallet estimates that the gas limit is too low, so the function call runs out of gas before the function call is finished.

BEP20: transfer amount exceeds allowance

Fail with error 'BEP20: transfer amount exceeds allowance'

Solution(s)

1. Use Unrekt.net to revoke approval for the smart contract you're trying to interact with

2. Approve the contract again, without setting a limit on spend allowance

3. Try interacting with the contract again.

Explanation

This happens when you set a limit on your spend allowance when you first approved the contract, then try to swap more than the limit.

BEP20: transfer amount exceeds balance

Fail with error 'BEP20: transfer amount exceeds balance'

You're probably trying to unstake from a 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 example, 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.

Solution(s)

Firstly, let the team know which pool you're trying to unstake from, so we can top up the rewards. If you're in a hurry to unstake and you don't mind losing your pending yield, try an emergencyWithdraw:

You can perform an “emergencyWithdraw” from the contract directly to unstake your staked tokens:

1. Find the contract address of the Pool you're trying to unstake from. You can find it in your wallet's transaction log.

2. Go to https://bscscan.com/ and in the search bar, enter the contract address.

3. Select Write Contract.

4. Click “Connect to Web3” and connect your wallet.

5. In section “4. emergencyWithdraw”, enter "0" and click “Write”.

This will unstake your staked tokens and lose any uncollected yield.

This will lose any yield that you haven’t harvested yet.

Explanation

This error tends to appear when you're trying to unstake from an old Syrup Pool, but there aren't enough rewards in the pool left for you to harvest when withdrawing. This causes the transaction to fail.

Other Issues

Provider Error

Provider Error No provider was found

Solution(s)

Install the official browser extension to connect, or read our guide on how to connect a wallet to CryptoSwap.

Explanation

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

Solution(s)

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

Explanation

You are connected an incorrect/ incompatible blockchain.

Internal JSON-RPC errors

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

Solution(s)

Try using an alternative wallet.

Explanation

Occurs when trying to remove liquidity on some tokens via Metamask. Root cause is still unknown.

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

Solution

Add more BEP20 BNB to your wallet and run the transaction again.

Explanation

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"}}}"

Solution(s)

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

Explanation

Cause unknown.

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

Solution(s)

Try these steps before trying again:

1. Increase gas limit

2. Increase slippage

3. Clear cache