Why Your Uniswap Swap Keeps Failing

The reassuring part first: a reverted transaction did not take your tokens. It cost the gas spent attempting it and nothing else. What it did do is tell you something, and the error text is worth reading before changing any setting.

One: slippage set below what the pool needs

The most common cause by a wide margin. You set a maximum acceptable price movement, the pool moved past it before your transaction was included, and the trade cancelled rather than filling at a price you had declined. This is the protection working. Raise tolerance a step at a time, and if it needs a great deal, ask why the pool is moving that fast.

Two: no gas left

Gas on Robinhood Chain is paid in ETH. If you swapped nearly all of your ETH for a token, there may be nothing left to pay for the next transaction – including the one selling it back. Keep a reserve that you never trade. This is the failure that traps people in a position rather than merely inconveniencing them.

Three: the approval

Selling an ERC-20 requires two transactions: one granting the router permission to move that token, then the swap itself. If the approval failed, was rejected, or was set to a smaller amount than you are now trying to sell, the swap reverts. Wallets usually prompt for both, and it is easy to sign the first and lose the second.

Four: the pool cannot fill your size

You can ask a pool for more than it holds. On a thin pool a large order either fails or fills at a price so bad that your tolerance stops it. The fix is not a setting – it is a smaller order, or several smaller orders, or a different pool. Check depth on Dexscreener rather than inferring it from the chart.

Five: the token will not let you sell

This is the one to take seriously. Some contracts permit buying and restrict selling, either outright or for everyone except a list of addresses. A swap that buys fine and fails every time you try to exit is the signature of a honeypot, and no slippage setting will fix it because the refusal is in the contract.

The order to check things in

1. Read the error. Most wallets name the reason and save you the guesswork.
2. Check your ETH balance for gas before anything else.
3. Try a much smaller test amount. If that fills, the problem was size or depth.
4. If a small sell also fails while buys succeed, stop trading it and check the contract on Blockscout.
5. Only then adjust slippage, and by small steps.

The instinct is to raise tolerance until something goes through. It usually does go through, at a price that makes the failure look like the cheaper outcome.