auto publish not working

Here’s my site:
Champagne Tastes

My posts that I save for future publication date are not automatically posting. I have a publication date and time set, and everything is set to ‘scheduled,’ but the time comes and goes and nothing gets published. Instead, the scheduling time says ‘missed’ in red instead of ‘scheduled’ in green.
I downloaded the WP Missed Schedule plugin as a temporary solution, and it does publish my posts, but sometimes as much as 2 hrs late. I’m trying to figure out what the problem is.

This blog was originally published through WordPress.com, and always published on time then, but since I’ve moved it to www.ads-software.com I’ve had trouble. Help!