As part of the verification procedure, the domain part of the email address is checked against the nameserver. This means that only Internet-style addresses are accepted, such as "nemo@msn.com", "pigeon@greenpeace.org", or "1234,5678@compuserve.com".
It is suggested that you choose a generic email address (one defined in your aliases file), such as "sales" or "info", rather than a person. You can alias the generic address to whoever currently has the job.