untrusted_cert_title error when reinstalling MacOS Sierra
You don't execute MMDDHHMMYY. You replace all those characters with the current date information.

If we were performing/entering this command in Terminal right now, since it is 16:14 for me on 05/01/18, we would enter the following command: date 0105161418 and then hit "enter/return".

01 - 05/01/18

05 - 05/01/18

16 - 16:14

14 - 16:14

18 - 2018