Ethereum Blockchain Explorer Open Source http://www.stes.tyc.edu.tw/xoops/modules/profile/userinfo.php?uid=3670142 So, when there is numerous transactions while in the mempool so you paid a relatively lower transaction payment, your transaction can stay unconfirmed for an extended length of time considering the fact that miners/validators will pick out transactions with larger fees to... https://www.instapaper.com/p/16800704