Swap troubleshooting: why transactions fail
Most failures are simple: gas, slippage, approvals, wrong network, or token quirks.
Top causes
- Not enough gas
- Slippage too low
- Missing approval
- Wrong network
- Token restrictions
Read the failure message
Wallets often show a short error. It may mention gas, slippage, allowance, or a token transfer failure. Treat the message as a clue, not a mystery.
Checklist for fast fixes
- Confirm you have enough gas for the network.
- Confirm the token is approved (and allowance is sufficient).
- Reduce trade size if price impact is high.
- Increase slippage slightly only if you understand the risk.
Gas settings and waiting
If the network is busy, a transaction can sit pending. Some wallets let you speed up (higher fee) or cancel (replacement transaction). Be careful: multiple pending transactions can confuse newcomers. When in doubt, wait for clarity before stacking more transactions.
Token quirks
Some tokens charge transfer fees, block certain wallets, or require special handling. If swaps fail repeatedly for one token while others work, the token itself may be the reason.
RPC and wallet issues
Not every problem is “the swap.” Sometimes the wallet or RPC endpoint is the bottleneck: stuck pending status, missing balances, or failed simulations. If the same transaction fails in multiple interfaces, it’s likely a chain or token issue. If it fails only in one wallet, try a different RPC or wallet.
Nonce confusion
Wallets send transactions in order. If you have an older pending transaction, newer ones may not confirm until the first one is resolved. Speed up or cancel only if you understand what you’re replacing, then wait for the network to update before trying again.