In most situations a domain can only be attached to a single nation*

Say you followed these steps to connect domain.com to example1.nationbuilder.com. You've also added [email protected] to your broadcaster and you are fully authenticated for blasting.

Now you want to connected domain.com to example2.nationbuilder.com. If you attempt to connect a domain that's already connected to another nation, you'll see this error:

A domain can only be attached to a single nation. You can contact us at [email protected] if you have feel like your domain should not be attached to any other nations and this message is a mistake. 

If you were to set up a broadcaster in the NationBuilder account example2.nationbuilder.com that used [email protected], you could still email blast. However, since domain.com is already attached to another nation, your [email protected] emails would not have a unique white label and would be generically authenticated. 

*The exception would if these nations are a part of a Network plan where subnations are involved.