Can only complete transaction when logged in

I am able to complete a purchase from the store successfully only when I am logged into the site.
We do not want customers to create accounts or login to Wordpress to make transactions.
If you are not logged in, the problem is that it keeps saying you have 0 items in your cart and you can't complete the transaction.
if you would like to test it, use OMGTESTING as the coupon code to check out (it will give you 100% discount).
I think I have turned off everything that requires customers to be logged in. Can you check? Thanks!