If you start a mock/practice draft, and then exit the draft room the draft clock will continue to run.

This may cause the clock to be at 00:00 when you return back a little (or even several days later).

If you are ready to start your official draft, and want to reset all the picks and the clock simply reset your draft: https://help.fandraft.com/en/support/solutions/articles/61000278701-how-do-i-reset-my-draft-

Alternative, you can just reset the clock to start running, by clicking the clock reset controller: