Blockchain Explorer Usdc https://www.demilked.com/author/brownelivingston04/ So, when there is a lot of transactions within the mempool and also you compensated a relatively minimal transaction charge, your transaction can remain unconfirmed for an prolonged time frame given that miners/validators will choose transactions with better costs first. These transactions remain in the mempool https://getidealist.com/story22479818/blockchain-explorer-api-the-smart-trick-of-explorer-blockchain-ethereum-that-no-one-is-discussing-https-cutt-ly-3rj9ygbc