Hey Christine,
Pretty sure it's an sbcglobal thing as I have received more than one email from an sbcglobal customer about this. I think our domain may be blocked for spam. If you have an sbc email addy, you could try calling your ISP and asking about unblocking us or you could signup using an alternate email if you have one.
Id love to get this figured out but im having trouble finding any contact info for sbc atm. I'll keep looking tho : )
R