Woocommerce cannot add to cart with CloudFlare

I am running Woocommerce site with CloudFlare paid service via hosting company. I am also using W3TC for caching, but disabled Browser Cache, Object Cache, and DB Cache (only page cache and CloudFlare).
I am facing a major issue with CloudFlare working with Woocommerce or browser, and I am hoping to get some pointers, tips, hints or solution.

All traffic is now https via CloudFlare. I see the page load fine. After clearing browser cache locally, I can add products to cart without logging in. But once I add anything to cart, I cannot login. I have to clear the browser cache again, then I can login. Once I’m logged in, I can add products to cart or do anything else, but as soon as I logout, I cannot add anything to cart nor log back in.

The site is: my site

What is going on? I cannot figure this out… Any help is greatly appreciated!

EDIT: Everything works as expected in “private” or “incognito” mode of browser.

• This topic was modified 8 years, 5 months ago by jonathankenbrown.