Our website uses S3 for media hosting (only images), with its own url (midia.xxxxxx.com.br) and certificate in "flexible" mode, mediated by Cloudflare (which acts as a primary DNS and proxy, we do not put our certificate on S3 because we use let's encrypt at source). Everything works fine, except for one detail: when we try to share a link in the Whatsapp application, the images offered by the opengraph tag cannot be embedded in the post. Whatsapp receives a 503 code. This does not happen with any other social network. For the rest, everything is ok.
Access to the bucket is completely public and the images can be opened normally in any browser. Browsing is properly guided by ssl (albeit forcedly, by Cloudflare), and everything else in media management and loading works fine... Does anyone have any idea how to solve this?