Usdt Trc20 Blockchain Explorer http://www.stes.tyc.edu.tw/xoops/modules/profile/userinfo.php?uid=3670142 So, if there is a large number of transactions in the mempool and you also paid a comparatively small transaction cost, your transaction can continue being unconfirmed for an extended time period because miners/validators will pick out transactions with increased fees to start with... https://guideyoursocial.com/story5499127/blockchain-explorer-usdt-new-step-by-step-map-for-blockchain-explorer-api-https-cutt-ly-3rj9ygbc