Explorer Link copyright https://www.instapaper.com/p/16800964 So, when there is a lot of transactions within the mempool and you simply paid out a relatively low transaction charge, your transaction can continue being unconfirmed for an prolonged length of time due to the fact miners/validators will pick out transactions with larger fees initially. https://numberfields.asu.edu/NumberFields/show_user.php?userid=6213549