Checkout on page not working

Hi there,

I searched and couldn’t find a resolution to this problem.

I am testing my checkout function out and it “Crashes” after inputting the shipping address. It times my sessions out and states “sorry, your session has expired” < return to homepage”

At the bottom near the “your order” I get an hour glass window. I assume its trying to calculate taxes, but why does it time out right afterwards?

Someone please help. We are launching our store soon and need it up ASAP. I have attached screenshots.