Page not found with new content
I believe this is a caching issue.

'The requested page could not be found.' is not the same as 'You are not authorized to access this page.'

Because you can see the page as the admin account but not as an anonymous user, I believe you can fix this issue by flushing your Drupal caches.

The admin account doesn't show cached content by default but the anonymous users do.

There are several ways to Clear Drupal's Cache but the simplest is likely to go to admin/config/development/performance.

If you use drush, simply run 'drush cc all'