There can be many reasons why the content is not visible in the embedded URL. Some of them are:
Unpublished content: Please make sure that the content in the embedded URL is published. If the content is not published, it cannot be displayed on the embedded URL.
Different setting at Mix level: In case of Embed type ‘News feed’, if you are not seeing some content from a mix - please make sure that there is no additional setting applied at a mix level like ‘Display in News feed’ option is disabled or the mix is pinned to the additional tab at channel or organisation level.
Unpublished embedded URL: Please make sure that the embedded URL is published or else the content cannot be displayed.
Deleted embedded URL: If the embedded URL is deleted, the content cannot be displayed.
In case the issue is not related to the above mentioned points, please contact us at firstname.lastname@example.org.