Log in as a Confluence administrator, click "Confluence Administration"> "Page and Attachment Security Enhancer"> "Configuration", and select "Attachment Download Restrictions".
.png?version=1&modificationDate=1647590871059&cacheVersion=1&api=v2&width=566)
"Restrict the types of attachments that can be downloaded" switch default: on.
"Restrict the types of attachments that can be downloaded" default: empty (no restriction).
"Allow preview and view of restricted attachments" switch default: on.