No information has been given from Verizon on this blockage of email service. I reckon even they dont know that there is some issue with email. Sounds like a website crash ,if it is then it will take several hours to clear the issue.
I have found a link that will help you on the very latest on this story.Hear what other users say about the service shutdown by visiting this page
Just hope for the best that the site come back to its old ways