Posts not showing on landing page

Okay, here’s what’s happening.

A couple of weeks ago I added 3 new categories to my category list.

When I tried to post to one of the categories, the post does not show up on my landing page. It shows up in my slider and when you click on the category, but not on the landing page.

I have temporarily fixed the situation by chosing one of the new categories and then an old category, such as uncategorized. However, I don’t want to keep doing that.

I have tried deactivating all of my plug-ins, I’ve checked the settings-reading and all is well there, I’ve tried deleting the categories and adding them again. I’m out of ideas!

Any suggestions?