Where I can remove "free email accounts are not allowed"

I need to remove "free email accounts are not allowed" from my form. When i checked preference section i can't able to view any option. 

That option is only available with the old interface of Jotform: http://jotform.com/?old

So please try to check the old interface of Jotform.

With the email field, you can remove the validation of "free email accounts are not allowed". Just open the email field properties, and set the following to "No".