I am creating a bot to buy and sell tokens on Uniswap through a smart contract. The buying part goes on well I buy the tokens uisng the smart contract I have deployed. But when it comes to selling, I have to send the tokens from my wallet to the smart contract then sell them. All this should happen in the smart contract. I use transferfrom and approve to make it possible to sell but the approve never works so I always get an error that I am trying to sell more tokens than I had approved.