The Verizon systems reject any email addresses with a "+" as an invalid email address, even though such email addresses are completely valid. http://en.wikipedia.org/wiki/Email_address#Valid_email_addresses
I tried Verizon support though they just repeatedly told me such email addresses are invalid. The fact that I regularly receive email to such an address demonstrates this is false. Anyone have any suggestions? I could of course use a different email address, but since I pay Verizon I don't think it is too much to ask for them to support standard and valid email addresses.