Unicom's iron powder, my Redmi 5p mobile phone screen lock password can't be determined.

The phone is locked. You must first determine whether the phone itself is locked or locked according to the prompt of the phone. If the mobile phone itself is locked, you need to enter the mobile phone password (see the mobile phone manual); If the card is locked, please enter the PIN code or PUK code on your phone. The initial value of the PIN code is 1234, and the PUK code is printed on the card embedded in the mobile phone card when buying the card. It is 8 digits, * * * has 10 chances to enter. After 10 times, the USIM card will automatically start the self-destruction program, making the SIM card invalid. Only go to the business hall to reissue the card.