If your card is blocked card or you have entered incorrect PIN three times, the program will request the PUK code (can be found on the same document as the PIN). Before entering the PUK code, check whether the digital certificate serial number, also found on the document with the PIN and PUK code, matches the serial number written on your digital certificate.
Start Nexus Personal.
Click the PIN button.
Select Unblock PIN.
Enter the PUK and PIN codes.
To complete the unlock process, click Finish.