Preview not working for scheduled posts

Hello

When the developer built our site, behind the firewall, post preview for scheduled posts worked. But now that the site is live, it does not work. Preview also does not work for viewing changes to a live post. We get an error message, “article not found”.

I have tried viewing posts in incognito browser. I have cleared cookies and cache for all time.

Thank you in advance!

Laura

The page I need help with: [log in to see the link]