When trying to swap certain tokens on Arbitrum, you may experience an issue where the ‘Swap’ button greys out and does not trigger your wallet when you click it. Or perhaps you'll receive the message above, "Unexpected issue with estimating the gas. Please try again." If you find yourself unable to sell a token, you should take note of whether or not that token has a tax on it. If it does, you are finding issue because it is not compatible with the Trident router that https://sushi.com/swap uses.
To use the old router which does support fee on transfer tokens, use the 1.0 UI at https://app.sushi.com/
When you go to sell your token, you will also need to increase slippage accordingly for the tax. If the token you are selling has a 7% fee for example, you’ll want to use around 8% at least which will also include DEX fees and price impact.
This also applies to removing liquidity. If a tax is levied upon removal, use the 1.0 UI to withdraw and increase slippage.
If none of this works and you cannot sell your token despite whatever you do, then take a moment to check the validity of the token you are trading. Is it a copycat coin of something else? If you search the address of it on https://arbiscan.io/ you can inspect the contract. A sure sign is if the contract name is generic (particularly MOON, COIN, CoinToken, iGOLD, KING) and has nothing to do with the actual token. Search through the contract a bit, if you see a function by the label of killself() or selfdestruct(), that’s another sure sign. Something like this could allow the creator to drain the trapped liquidity to a location of their choice. Additionally, you may see use of blacklists or greylisting to prevent buyers from selling or moving the token after it has been purchased.
Besides this, you’ll also would to do your due diligence in checking the website, socials, and documentation of your token – whether these exist or not, it is a good indication of legitimacy. When monitoring the buys and sells of it on an application like DexTools or DexScreener keep an eye on sells. If only one address is selling and all of the others are only buying, there may be a reason for that. You can use a service such as https://detecthoneypot.com/ to analyze the token you are trying to trade with simulated transactions. It won’t always catch all of them, but in many cases will alert you if a token contract is malicious. You should be able to find several different websites like this if you search around the web. There's also Tenderly if you have the know-how on how to manually simulate transactions yourself.
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