Cloud CDN is used behind an HTTP(S) load balancer and web servers are configured to compress responses, but Cloud CDN is serving uncompressed responses. What is the likely cause?

Cloud CDN typically requests content from the backend by adding a Via header to the request. Many web servers, by default, will not compress responses for requests that include a Via header, as this header indicates the request has passed through a proxy or gateway. To ensure Cloud CDN serves compressed content, the web servers must be explicitly configured to compress responses regardless of the presence of a Via header. Incorrect options: Cloud CDN does not have a separate compression configuration; it relies on the backend to provide compressed content. While different compression types could cause issues, the primary problem with Via headers often prevents any compression from occurring at the web server level. Different compression types on web servers behind the load balancer would lead to inconsistent compression, but the fundamental issue here is the web servers' general refusal to compress for proxied requests.