Further extract or download ad creative such as images and text for an individual ad

The result of the API query is somewhat very abstract, and it seems the _ad_snapshot_url_ is temporary link.
I tries to make a query of an individual ad but I have got the error below. Anyone who might have an idea about the root cause?
I have both **pages_read_engagement permission** and **pages_read_user_content permission** added before making the call.

Error :
_{
    "error": {
        "message": "(#10) This endpoint requires the 'pages_read_engagement' permission or the 'Page Public Content Access' feature or the 'Page Public Metadata Access' feature. Refer to https://developers.facebook.com/docs/apps/review/login-permissions#manage-pages, https://developers.facebook.com/docs/apps/review/feature#reference-PAGES_ACCESS and https://developers.facebook.com/docs/apps/review/feature#page-public-metadata-access for details.",
        "type": "OAuthException",
        "code": 10,
        "fbtrace_id": "Ay1JovtZ_DRs3e1SX3rksWA"
    }
}_