Are you getting this message when you try a site: search on Ask.com?
They may be prioritizing some queries over others. There are two solutions to get it to work:
1. If there is particular word that appears on every page throughout your site, as part of your site name or a copyright notice, for example, you can use
2. Access Ask through a country-specific domain, like [uk.ask.com,...] and try a site:www.example.com query there.