Does Domain Mapping support .us domains?

I am trying to map the domain americanpri.us on my multisite install. I have the plugin working on my other sites within the multisite, but when I enter the domain, I get the error message "Domain Name is Invalid" does this plug in not support .us? or did I mess this up when pointing it from go daddy? the @ record seems to be correct I am wanting to point the domain to 66.228.37.136