Article - CS364789
Unable to edit ThingWorx mashups due to Browser Content Security Policy error "Refused to frame 'http://<servername>/' because an ancestor violates the following Content Security Policy directive: "frame-ancestors 'none'""
Modified: 29-May-2026
Applies To
- ThingWorx Platform 8.5 to 10.1
Description
- ThingWorx mashups appear inaccessible due to browser security errors
- Unable to see mashups in the Design view preview
- Mashup runtime displays correctly when loaded in a separate window outside the Composer
- Firefox Developer console shows error:
Content Security Policy: The page’s settings blocked the loading of a resource at https://<servername>/Thingworx/Composer/index.html (“frame-ancestors”)" - Chrome developer tools console shows error:
Refused to frame 'http://<servername>/' because an ancestor violates the following Content Security Policy directive: "frame-ancestors 'none'".
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