WooCommerce Checkout Issue

Hi. When I want to proceed to checkout my payment options, the loading is never ending. I have found some people with the same problem, but their solutions doesn’t work.
In console there’s:

www.mysite.com/?wc-ajax=update_order_review:1 Failed to load resource: the server responded with a status of 403 ()

Please help, I’m so done with it.
After disabling the Sydney theme, it’s working just fine.

Hi,

Which version of Sydney theme are you running? Is it the latest?

Regards,
Kharis
aThemes Support