file that is hosted in a private Cloud Storage bucket. You are using the USE_ORIGIN_HEADERS cache mode. You receive an HTTP 403 error when opening the file in your browser, and you see that the HTTP…

Question

Options

• AEnable negative caching for the backend bucket.
• BChange the cache mode to Force cache all content.
• CConfigure a Cloud Storage bucket permission that gives allUsers the Storage Legacy Object
• DIncrease the default time-to-live (TTL) for the backend service.

• A
  5% (1)
• C
  85% (17)
• D
  10% (2)

Explanation

The HTTP 403 error with a Cache-Control: private, max-age=0 header indicates that Cloud CDN is successfully reaching the Cloud Storage origin, but the origin is returning an access-denied response because Cloud CDN's service account does not have read permission on the object. In USE_ORIGIN_HEADERS mode, Cloud CDN faithfully forwards the origin's response - including the 403 and the private cache header - rather than caching it. The fix is to grant allUsers the Storage Legacy Object Reader role on the bucket, making objects publicly readable so Cloud CDN can fetch, cache, and serve them. Enabling negative caching (A) would cache the 403 itself. Changing cache mode (B) or adjusting TTL (D) cannot overcome a permissions error at the origin.

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