The root cause relates to a routing change that was made as part of our removal of TLSv1.0 protocols from certain FoxyCart.com subdomains. Though these changes were tested before and after the change, the request volume didn't trigger a security automation that happened when we made this change in our production environment. Once we became aware of the issue, we quickly worked to diagnose and correct it.
We apologize for any inconvenience this may have caused. We have resolved the issue and have an improved approach ready to be further tested and deployed.