What Is ‘Transaction Dropping’ and Why Does It Happen in a Congested Mempool?

Transaction dropping occurs when a node removes an unconfirmed transaction from its Mempool, usually because it has been waiting too long or the fee is too low compared to newer, higher-fee transactions. In a congested Mempool, miners prioritize higher-fee transactions, causing low-fee transactions to be ignored and eventually dropped by nodes to free up memory.

The user must then resubmit with a higher fee.