I got a old box of ornaments and I can only put one out of the 3 on it why is that. It keeps saying to many of the item but none of them are one but one blue one

They're not stacked on top of each other up in the corner? That happened to me a few hours back. They wouldn't add and then they add added at once.

Also, maybe try changing their stacking order by using the up or down arrows. Might bring them far enough forward that you can see them.

thanks I will try that