Failure = No change. At times due to congestion or if you're completing multiple transactions back to back, it's possible a transaction could fail. Failure means no one involved in the trade or update got affected in any manner. It might not visually look like that right away because of the congestion but it will appear back in its previous state. Please press the resync button on the asset page to manually sync the UI to the correct state.
Failure = No charge. On Cardano if the transaction fails, you are not charged any ADA, unlike Ethereum where when a transaction fails, you are still partially charged a fee. The only times you are charged, you will also see a confirmed Cardanoscan link on the "Activity" tab.
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