The e-mail address of the user should be entered in the Organization section of TeamCenter. You will find the user under Persons. (yes there are 2 locations where a User is configured)
I am assuming you are talking about a real e-mail and not the Teamcenter Envelope?
Ronald van den Broek
Senior Application Engineer
Winterthur Gas & Diesel Ltd
NX9 / TC10.1.2
Building new PLM environment from Scratch using NX11 / TC11