If you run into the scenario where you want to prevent calling to a specific number (or an area code) you can navigate to Manage Campaigns > DNC Numbers.
If you need to generate a new record, click "Add.". You will need to fill out two pieces of information; both are required: Phone number/Area code and reason. In the first field, we can add a full 10 digit phone number or just a 3 digit area code. The reason is simply for client reference.
Once you've input the data and press "OK," a new record will be generated for the specified data.
You can go back and edit a record at any time if you made a mistake with a number or the reason. You may also delete a record if you wish to call a phone number or area code again.