The CLI is typically the main number or billing telephone number. As the owner of a number, you can set limits and destinations to that number. If you are unable to call a specific or all Toll free numbers, this number may be set to reject them on purpose. This is especially true of demo accounts in which the number has not ported over to us. If you experience this, please open a ticket with us to check with the carrier and these possible settings.
Another reason would be that a specific toll free prefix is not in your Rate Sheet. Please check your Profit Center/IP Minutes for the complete list of dial codes and your specific Toll Free Dial code.