I had the same problem and Just found a SOLUTION.
I started deactivating my pluggins one by one until I found the one that had conflict with woocomerce, I eventually found that WP-Mail-SMTP was the pluggin causing the order confirmmation not to show up and made spinner to run forever. After deactivating WP-Mail-SMTP eveything works fine.. I hope this canwork for you as well.. It could be another pluggin, just check ..Cheers guys !