Swapping tokens on the Base network using Phantom is usually smooth. However, some swaps may fail due to network conditions, token behavior, or liquidity issues. This guide outlines common causes and provides steps to help you troubleshoot.
Insufficient funds
All transactions on the Base network require ETH to pay for gas fees. These fees vary based on network congestion and transaction complexity.
Why it happens
Users often have ETH on the Ethereum mainnet, but not on Base. If you don’t have enough ETH on the Base network, the transaction will fail—even if your total ETH balance across networks appears sufficient.
What to do
- Check your ETH balance on Base. Assets on Ethereum don't count.
- Use a gas tracker like Etherscan Gas Tracker to estimate required fees.
- Transfer ETH to Base using a bridge if needed, then retry the swap.
Note: Without ETH, no transaction on the Base network can be completed.
Slippage tolerance exceeded
Slippage is the change in price between when a swap starts and when it completes. Phantom sets a default slippage tolerance of 0.5%.
Why it happens
Phantom sets a default slippage tolerance. If the price moves beyond this range before the transaction completes, the swap is canceled.
What to do
- Increase your slippage tolerance in the swap settings.
- Turn on auto slippage to automatically adjust for price volatility.
- Retry the swap with a slightly higher setting.
Important: Use caution when raising slippage. Higher slippage may lead to worse exchange rates.
Liquidity provider issues
Phantom uses the 0x aggregator to find the best swap rates from decentralized exchanges (DEXs) on the Base network. But swaps can fail when liquidity is low for the token pair.
Why it happens
If there’s not enough liquidity, the aggregator can’t find a matching offer to complete your trade.
What to do
- Retry later. Market activity may increase, improving liquidity.
- Swap a smaller amount. This reduces pressure on limited liquidity.
Note: The 0x aggregator optimizes rates across DEXs, so the issue is often resolved when liquidity improves on one or more platforms.
Price impact
Price impact is how much your trade changes the market price. If the token pool is small, even modest trades can move prices significantly.
Why it happens
When a liquidity pool is shallow, larger trades affect the price more. This often happens with new or thinly traded tokens
What to do
- Break large trades into smaller ones. This minimizes your impact on the pool.
- Trade during busy periods. More liquidity usually means less price impact.
- Check liquidity in advance. Use blockchain explorers or DEX interfaces to check the token’s pool size.
Warning: If swaps consistently fail and liquidity is very low, the token may be untradable—and funds could be unrecoverable.
Malicious account error
If you see a message that the swap failed due to a malicious account, the token is likely a scam. These tokens are often designed to block swaps and trap funds.
Why it happens
Scam tokens block swap functionality, making them impossible to trade.
What to do
- Stop interacting with the token. Do not approve or transfer it again.
- Avoid future exposure. Only use verified tokens and check token contracts using trusted tools.
Important: Scam tokens cannot be swapped. Unfortunately, funds tied to them are usually unrecoverable.