in my case it’s just permalink problem, when i set permalink to default it works perfectly.
actually i want to make url neat, but yeah.. at least i can use my woocommerce.
ya, i have the same problem…
i was try to debugging,
i try to show all SESSION value
when i add product to cart, the product added to SESSION,
but everytime i go to checkout page or view cart page or detail product page, product data at SESSION has gone.
but, i still don’t know why could this happened.