Hi Carol:
The military and the airlines and the government have midnight as the last of the day, not the beginning of a new day. Maybe the IT types that created the boards you speak of didn't know that. I usually get my votes in sometime during the day on Sunday, since my deadline is 9 p.m. anyway. One second after 9 p.m. cooks it for me.
You're in Missouri, and CST, so it is 11 p.m. for you. If you did it just before your midnight, you were an hour too late.
Artemis
