Cloudflare has detected that your configuration has enabled our Authenticated Origin Pulls feature.
Recently, we renewed the certificate that our edge network presents to your origin due to the
upcoming expiration of the current certificate on January 11, 2020.
You can find the updated certificate and follow the instructions for updating popular origin servers in
this Cloudflare Help Center article:
https://support.cloudflare.com/hc/en-us/articles/204899617/.
When enabled, this feature adds an extra verification on the SSL handshake to ensure the request comes from Cloudflare.