When I have WooCommerce Views enabled, I get a blank error on the checkout page. Therefor, users can't complete the checkout and thus can't get to the payment provider. When I disable WooCommerce Views, everything works well.
When I enable debug in wp_config, the order overview and payment method field keep having a spinning loading circle on them, I don't get any debug information. I would like to give you FTP credentials, but I can't find how to make a reply private...
The blank error is after you filled in all the fields... the error you're seeing is because you didn't fill in the fields yet. The red bordered error at the top is put there by me of course.
I did some more testing. It seems there's a conflict between WooCommerce Views and Yoast SEO. If I disable one of those, everything works fine. However, if they'e both active, the error occurs.
If you have other tickets with similar issues, why didn't you say "try to disable Yoast" instead of letting me spend a lot of time on testing? I provided the login details, so you could have checked this scenario yourself as well...