Tron Blockchain Explorer https://output.jsbin.com/nisuteliyi/ So, when there is a large number of transactions within the mempool and you compensated a comparatively low transaction cost, your transaction can stay unconfirmed for an prolonged timeframe considering that miners/validators will pick transactions with greater fees initially. The mempool in essence queues the transaction https://www.bitsdujour.com/profiles/BcYkMI