Contact marked as Opted Out

In October I sent a newsletter to everyone and 552 were delivered. I have 677 contacts. When I sent the Black Friday newsletter to the 667 contact only 16 were delivered.

I created the Newsletter first and saved it as a template. I then went to select all my contacts and selected send Broadcast then selected my template. When I did that is warned me that 660 people would not receive the email. When I clicked the See Why link it says that the reason the email was skipped (on most of them) is Opt-out: Admin.
I have not opted out anyone. Do you know how to fix this?

If they clicked unsubscribe they’d be opted out but I’ve also seen users (and va’s) accidently bulk opt out contacts.