Can't consign anything - sell list is just blank

So when I first got the game, the consignment store worked fine. I could buy and sell all kinds of things. But now I can only buy from there. I've tried it with several different items, even some that are in the "buy" list (so I know you can sell them) but when I click on the "sell" tab, the list is just empty. I have tried putting the items in my inventory, in my family inventory, just in my house but nothing seems to work. I have also tried rebuilding the consignment store somewhere else but it still doesn't work. I'm using Sunset Valley at the moment but it's the same with all of the other towns I've tried. What am I doing wrong?