SBCGlobal repeatedly add our mail server to their antispam blacklist and as such we cannot get mail through because their server rejects it. I have written to them on a number of occasions and have been removed, only to be added back into the blacklist again a few days later.
The quickest option to get your notifies flowing again is to login and change your e-mail address to a non sbcglobal.net address (change your PRIVATE address not your public one). A slower approach would be, as a customer of sbcglobal.net, to write to them and ask why they keep blocking deardiary.net servers!
Sorry for the inconvenience but I'm not going to keep writing to them every couple of days to get removed from their blacklist, they'll need some pressure from inside to figure out why their blacklist is being over protective.