You may need to reset your PIN code if a suspicious activity has been reported by your admin; when a wrong PIN code has been entered three times in a row, or if your PIN code doesn't work - afterwards your card is automatically blocked.
If you wish to change the PIN code of your MasterCard, just go to the 'Cards' section and select your card.
In the the right-side panel, click on 'Reset PIN code'. Then you'll be able to set a new code for your card.
Important: You need to make a withdrawal from an ATM in order to activate this new PIN code.