Transactions on the Cardano network have a time-to-live (ttl) attribute. When you submit a transaction and the ttl (a given slot number) is reached before the transaction gets processed by the network the transactions expires and fails.
In this scenario, the transaction status indicator shows
To create a new transaction, you first need to remove that failed transaction. This releases the funds (UTXOs) used by the failed transaction and makes them available for a new transaction.
1. Go to the Transactions tab
2. Open the failed transaction details
2. Click on Remove failed transaction
4. Create and send a new transaction.