For me if I try to open them in browser, it shows this error:

{"error":{"code":"FileAccessDenied","message":"Access to this file was denied for your application.","status":403,"rtfm":"https://github.com/Redgifs/api/wiki/Embedding-gifs#file-access"},"docs":"https://github.com/Redgifs/api/wiki/Embedding-gifs#file-access"}