In order for the email to be valid the domain must also be valid. Toolset validation also checks to see if the email domain is valid. If it isn't then the verification of the email will fail.
This is the technical support forum for Toolset - a suite of plugins for developing WordPress sites without writing PHP.
Everyone can read this forum, but only Toolset clients can post in it. Toolset support works 6 days per week, 19 hours per day.