Troubleshooting Common Errors on Decentralized Exchanges

Navigating decentralized exchanges (DEXs) like DexySwap can be empowering, but encountering unexpected errors may disrupt your trading experience. Whether you're swapping tokens, adding liquidity, or staking in syrup pools, technical hiccups are common—especially in fast-moving blockchain environments. This guide breaks down the most frequent issues users face and provides clear, actionable solutions to get you back on track.

Core Keywords

• DEX troubleshooting
• slippage tolerance
• liquidity pool errors
• transaction failed
• insufficient output amount
• BEP20 transfer issues
• gas limit adjustment
• wallet connectivity problems

These keywords reflect real user search intent and are naturally integrated throughout this guide for optimal SEO performance.

Common Exchange Errors and Fixes

INSUFFICIENT_OUTPUT_AMOUNT

"The transaction cannot succeed due to error: PancakeRouter: INSUFFICIENT_OUTPUT_AMOUNT."

This error typically occurs during a token swap when the expected output falls below the minimum threshold set by your slippage tolerance—or when liquidity is too low.

Solutions:

1. Refresh the page and retry after a short delay.
2. Reduce the swap amount to minimize price impact.

3. Increase slippage tolerance:

   • Tap the Settings icon on the swap interface.
   • Adjust slippage slightly upward (e.g., from 0.5% to 1%).
4. Enter amounts with fewer decimal places to avoid precision-related mismatches.

👉 Learn how to optimize your swap settings for better success rates.

INSUFFICIENT_A_AMOUNT or INSUFFICIENT_B_AMOUNT

"Fail with error 'PancakeRouter: INSUFFICIENT_A_AMOUNT'"

This appears when adding or removing liquidity from a pair where one token’s balance is insufficient due to price fluctuations or outdated data.

Fix:

• Refresh the page first.

• If the issue persists:

  1. Open the settings menu on the liquidity page.
  2. Slightly increase your slippage tolerance.
  3. Retry the action immediately.

Low liquidity pools are more prone to such errors—consider splitting large transactions into smaller ones.

PancakeRouter: EXPIRED

"Transaction reverted: PancakeRouter: EXPIRED."

This means the transaction deadline passed before confirmation. Most wallets set a default expiration (often 20 minutes), and delays in signing can trigger this.

Solution:

• Generate the transaction again.
• Confirm (sign and broadcast) it immediately without delay.

To prevent recurrence, ensure your internet connection is stable and wallet is responsive before initiating trades.

Pancake: K

"Transaction reverted: Pancake: K."

This rare error often occurs with tokens that have built-in fees (like SafeMoon) or rebasing mechanisms. It relates to internal constant product formula violations in the AMM model.

Workaround:

• Swap direction matters. Try modifying the “To” field first so that “From” becomes estimated.
• Initiate the swap right away to reduce timing risks.

Pancake: TRANSFER_FAILED

"Execution reverted: Pancake: TRANSFER_FAILED."

Common with restorative rebase tokens like tDoge or tBTC, which adjust balances automatically. These tokens may fail if you attempt to spend nearly 100% of your balance.

Recommended actions:

• Keep at least 30% more than the intended trade amount in your wallet.
• When selling all, use 69–70% of your balance instead of 100%.

Additionally, some malicious tokens restrict trading via smart contract logic—especially those received via unsolicited airdrops. Always research token contracts before interacting.

👉 Stay safe from scam tokens with proactive verification tools.

High Price Impact & Transaction Failure

If you see "Price impact too high" or general failure messages:

• You're likely trading a large amount in a low-liquidity pool.
• The system expects significant slippage, risking loss.

Resolution:

• Trade smaller amounts across multiple transactions.
• Increase slippage tolerance via settings (up to 12% for taxed tokens).

estimateGas Failed

"This transaction would fail. Please contact support."

This critical error indicates the blockchain predicts failure upon execution.

For BNB pair liquidity removal:

• Select “Receive WBNB” instead of BNB before proceeding.

For token swaps:

• The issue likely lies within the token’s smart contract.
• Contact the project team directly, as only they can resolve contract-level restrictions.

Cannot Read Property 'toHexString' of Undefined

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

Frequently reported on Trust Wallet (mobile) during swaps.

Steps:

1. Retry with increased slippage.
2. If unresolved, switch to an alternative wallet like SafePal or MetaMask.

Wallet compatibility issues are common—using updated, reputable wallets reduces risk.

Execution Reverted: TRANSFER_FROM_FAILED

"TransferHelper: TRANSFER_FROM_FAILED."

This happens when:

• You don’t have enough balance.
• Or, you haven’t approved the contract to spend your tokens.

Fix:

1. Confirm sufficient token balance.

2. Grant proper allowance:

   • Go to the token approval section.
   • Approve the DEX contract for the desired amount.

Use tools like Unrekt.net to revoke and reset allowances securely if needed.

Syrup Pool & Staking Issues

BEP20: Burn Amount Exceeds Balance

"BEP20: burn amount exceeds balance."

Occurs when unstaking from SYRUP-based pools without enough SYRUP tokens.

Solution:

• Buy SYRUP equivalent to the CAKE amount you wish to unstake.
• Example: Unstaking 100 CAKE requires at least 100 SYRUP.

Out of Gas Error

"Contract execution failed: out of gas."

You’ve set too low a gas limit, not gas price.

Fix:

• Manually increase the gas limit in your wallet.
• A value of 200,000 is usually sufficient.
• Refer to your wallet’s documentation (e.g., MetaMask) for guidance.

Transfer Amount Exceeds Allowance or Balance

Two similar but distinct errors:

Exceeds Allowance: Contract lacks permission.

• Revoke old approvals via Unrekt.net.
• Re-approve without spending limits (or set appropriately).

Exceeds Balance: You’re trying to send more than available.

• Check pending transactions tying up funds.
• For syrup pools with depleted rewards, consider emergency withdrawal.

Emergency Withdraw from Syrup Pool

Lose unclaimed yield? Use emergencyWithdraw:

1. Find the pool’s contract address (via transaction history).
2. Access it on BscScan and select "Write Contract."
3. Connect your wallet.
4. Under "emergencyWithdraw," enter 0 and click Write.

⚠️ This skips reward collection—only use in urgent cases.

Prediction Market Issues

Can't Claim Winnings?

Check eligibility directly on-chain:

1. Visit the prediction contract on BscScan.
2. Go to "Read Contract" > "claimable."

3. Input:

   • Round ID (epoch)
   • Your wallet address (user)

4. Query result:

   • "true" = claimable
   • "false" = already claimed or ineligible

Note: Website UIs often lag behind blockchain data—on-chain checks are definitive.

Wallet & Network Errors

Provider Error – No Provider Found

"No provider was found."

Cause: Missing browser extension (e.g., MetaMask, Binance Chain Wallet).

Fix: Install the wallet extension and reload the page.

Unsupported Chain ID

Switch to Binance Smart Chain (BSC) manually in your wallet settings. Most DEXs operate on BSC—ensure network configuration matches.

Internal JSON-RPC Errors

Examples:

"Insufficient funds for transfer"
"Transaction underpriced"

Solutions:

• Add more BNB for gas fees (must be BEP-20 format).
• Increase gas limit and retry.
• Clear browser cache or switch devices/networks.

ethjs-query Formatting Errors

"Swap failed: handle request error"

Possible causes include network congestion or corrupted session data.

Try:

1. Increase gas limit
2. Raise slippage
3. Clear browser cache
4. Restart wallet connection

Profile & Username Issues

"No Pancake Collectibles Found"

Even with NFTs, this message may appear temporarily due to backend syncing delays.

Workaround:

• Disconnect and reconnect your wallet.
• Retry profile creation.

Username Check Keeps Spinning

Likely causes:

1. Multiple wallet extensions installed (e.g., both MetaMask and Trust Wallet).
2. Temporary network latency.

Fix:

• Disable all but one wallet extension.
• Reconnect and retry username setup.

Conflicts between providers are outside DEX control—single-wallet setups work best.

Frequently Asked Questions (FAQ)

Q: What is slippage tolerance, and why does it matter?
A: Slippage tolerance is the maximum price change you accept during a trade. Too low a setting causes failed swaps in volatile or illiquid markets.

Q: Why do some tokens fail even with enough balance?
A: Tokens with transfer taxes or rebasing mechanics alter actual spendable amounts. Always leave a buffer when trading such assets.

Q: How do I know if a token is malicious?
A: Check its contract on BscScan for suspicious functions like blacklist, pause, or restricted selling. Avoid tokens from unknown airdrops.

Q: Can I recover lost yield from emergencyWithdraw?
A: No—emergency withdrawal forfeits all unharvested rewards. Use only when necessary.

Q: Why does my transaction fail even with high gas?
A: High gas price doesn’t fix logic errors. Ensure sufficient balance, correct approvals, and compatible token mechanics.

Q: Is it safe to increase slippage above 12%?
A: Only for known taxed tokens like SafeMoon. Never raise slippage for standard tokens—it increases risk of sandwich attacks.

👉 Maximize your trading efficiency with advanced DEX strategies.