"Search" Problems

Hi Gurus. I have a problem I can’t seem to find a fix for.

My site has a search box in the header. When I search it, it returns with an error page. But, I have my WPPA+ Plugin Widget search on my sidebar and the search function works great. I would like to know if theres a way to make the search box that is in my header work the exact way that my widget search works? Below is a link so you can see what I am talking about:

https://www.thehouseofcakes.org/photo-albums/

Thanks so much to anyone that helps out!