I have a problem with certain e-mail messages getting blocked by Verizon. These messages are from user forums; Microsoft Community News Groups, Mozillazine Forums (Firefox & Thunderbird) and Safer Networking Forums (SpyBot). The messages are those that I expect when I request to be notified of a post to a selected thread. They simply never arrive. I have put these sites in the Verizon White List and in the Safe List for my Verizon account. Verizon denies blocking the messages. I really don’t think the problem is on the sending end. It is unlikely that three sites would have a problem.
Do any of you have a similar experience and perhaps a solution?

Thanks
Frank Camp
Dell Dimension 8400, Winxp SP2, ISP Verizon DSL