Problem inviting a parent

I successfully set up the primary account and have received notifications with that account (a hotmail address).  I have added my wife's email address (an earthlink.net address) to the notifications and have tried inviting her through the Invite a Parent process, but she never receives any emails.  I have successfully tested both with a test gmail account.

 

Is there a known issue with earthlink.net addresses?

 

-Steve