After some Samsung users restart their devices, they see "Use password after restart. Your password contains at least 4 digits, including at least 1 letter" notice on the screen. And sometimes when they switch off their devices, they need to enter password to turn off phone. It will require a password even you do not have a password. If you had set up password, it would declare the password incorrect and ask you to try a new password. Samsung S10 has been reported this issue due to software