I bought a mac mini at the first start, entered the password, entered the system. I saw that it was showing the time incorrectly, got into the date and time settings, clicked on the lock, entered the password and it is incorrect, what should I do in such a situation?
Mac mini, macOS 11.2
I can't say why this would happen, but I think resetting the computer's password might solve the problem. It sounds as if you purchased a used computer. Maybe it has something to do with what the prior owner did. Apparently, they did not clean the computer per Apple's instructions. Here is the reset link. Hope it works for you.
Change or reset the password of a macOS user account - Apple Support
Invalid password
