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.

What Is the Mempool and How Is It Exploited for Front-Running in Crypto?
What Is a “Mempool” in Cryptocurrency and Why Is Its Size Important to Transaction Fees?
What Is the Difference between a Node’s Mempool and the Global Set of Unconfirmed Transactions?
How Do Full Nodes Share Mempool Data to Improve Network-Wide Fee Estimation?
What Is a ‘Mempool’ and How Does It Relate to Transaction Fees?
In a Congested Network, What Is “Transaction Latency” and Why Does It Increase?
What Happens If the Mempool Becomes Congested?
What Criteria Must a Transaction Meet to Be Accepted into a Node’s Mempool?