Media gallery preview is not working on version 11 for some pages

There are a few places where permitted file types can be defined. 

File options are available when viewing the Media Gallery and navigating to Manage > Manage Gallery > File Options:

The Allowed File Extensions and Restricted File Extensions lists can be used to define the list of allowed or restricted file types by file extension. Note that this list is limited to the file types allowed for all media galleries (set in Administration > Applications > Media Galleries). If you make any changes, be sure to click Save to commit the changes.

The file type must also be available for upload at the Site level (set in Administration > Moderation> Files) but if you can upload the files to other areas in your site this should not be the issue.

More information related to Media Gallery Permissions can be found here. 

oloera You can also check Administration > File Viewers > Document Viewer > Documents to filter on "Not Processed" or "Error" to see if the specific media gallery files you're looking at are encountering other issues. Maybe they need to be reprocessed?

Hi, team. We found a separate issue. The Media Gallery file widget was removed from this gallery page, which did not allow the preview to display on the page.