The most common reasons for your withdrawal being declined are 

- insufficient funds, 

- entering a wrong pin number or 

- accidentally freezing your card in the Moneybase app.

Usually you will see the reason in the dashboard and also in the push notification

Kindly check the 'cards' section in the app to ensure your card is not frozen and also the security section to ensure that your security settings allow the ATM transactions. Also check that you have sufficient balance.