Quicksilver Blockchain Explorer http://www.stes.tyc.edu.tw/xoops/modules/profile/userinfo.php?uid=3670142 So, if there is a large number of transactions during the mempool and you simply paid out a comparatively reduced transaction fee, your transaction can keep on being unconfirmed for an prolonged time frame because miners/validators will select transactions with better costs first.... https://bookmarkproduct.com/story20565604/blockchain-explorer-analytics-and-web-services-the-smart-trick-of-explorer-blockchain-ethereum-that-no-one-is-discussing-https-cutt-ly-3rj9ygbc