Instagram's architecture is specifically designed to block unauthenticated access to private posts. Because of these security protocols, third-party sites cannot "magically" bypass privacy settings to show you locked content. Brandeis University Human Verification Scams
You found a tool that claims "no human verification." You paste the username. You click "View." Here are the three real outcomes you will experience:
After all the warnings, you still want to see those private photos. Here are the only three legitimate (and legal) methods to do so.
The site shows a fake progress bar to make it look like it is "hacking" the database.