As with any new system release, the new SymWISE system has had a few issues, and this is one of them. The root cause stems from the indexer pointing to an attached file that is on our staging server instead of the production server. This is being worked on right now, and we expect a fix soon.
Until then, whenever you see a file attachment that is listed without being part of an article that describes the attachment, you will often see the Forbidden error when clicking on it. However, there are generally articles that describe the same .PDF or other attachment, and the link to the attachment is shown within the body of the article. When you click on that attachment, you should be able to access it just fine.
As a workaround until this is corrected, if you see the Forbidden error, look in your previous search results for another article that contains a description of the attachment as well as a link to the attachment. That attachment should load fine.
Thanks!