Most failed links come down to one of a few causes: the link was copied incorrectly (missing characters at the end is the most common), the post was deleted or made private after the link was shared, or the account itself is set to private.
Check the source first
Start by opening the link directly in a browser — if Instagram shows "page not found" or asks you to log in to view it, the problem is on the source side, not the resolver. If it opens fine on Instagram but fails here, double-check you copied the full URL, including everything after the post ID.
Private accounts aren't supported
If the account that posted the content is private, a downloader can't access it — only the account owner or their approved followers can see it in the app. That's not a bug; it's how Instagram protects private accounts.
Carousel posts
Multi-photo or multi-video carousel posts sometimes need the link to a specific slide rather than the overall post. If only the first image or video comes through, look for a way to grab that individual slide's link instead.