“Proceed to Checkout” redirects to Cart

When I’m on the cart page and click “Proceed to Checkout” …The checkout page is redirecting back to the cart page for some reason.

I’ve tested on several different computers in my house and on my phone and in incognito mode… different browsers. Hostinger support seems to say it’s working fine…?
It seems to be inconsistent and I can’t tell whats going on. Thanks in advance for any help debugging.

The page I need help with: [log in to see the link]