Tx Doctor / EVM error library / Safe transfer failed (STF / TF / TransferHelper)
EVM error: Safe transfer failed (STF / TF / TransferHelper) (STF)
The router could not pull tokens from your wallet. Uniswap-style routers report this as the three-letter code STF (safeTransferFrom failed) or TF, PancakeSwap as TRANSFER_FROM_FAILED — all mean the same thing: balance, allowance or token rules blocked the pull.
Why it happens
- The token allowance for the router is too low or was already spent.
- The wallet balance dropped after the transaction was built (another pending transaction took it).
- The token is fee-on-transfer, so the router received less than the amount it tried to move.
- The token blocks transfers for your address (blacklist, pause, trading not enabled yet).
How to fix it
- Open the token on the explorer and check allowance(spender, router) — approve the exact router the transaction called.
- Refresh the balance and rebuild the swap with the amount you actually hold.
- For a brand-new token, check whether trading is enabled; a launch-block buy always reverts.
- Revoke and re-approve if the allowance shows a non-zero but insufficient value (common with USDT).
What it looks like in the wallet or explorer
execution reverted: STF (Uniswap router: safeTransferFrom failed)
Seeing this right now? Paste the transaction hash — the tool finds the chain and decodes what actually failed.
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