can't sign up, keeps erasing the users I invite on team account

I am trying to create a 25 user team account. after I enter about 10 emails of team members to add, it erases the entire list and shows this error:

You must add at least one member.
These admins are not invited team members: jnolte@reachforce.com, rvanderwerf@reachforce.com

what gives?