C.M. of Montgomery Village, sorry that Verizon changed their smtp mail server port without letting you know. Probably they ran on ports 25, and 587 in parallel for a long time, and it was just last week that they decided to cut off 25.
Back when they made port 587 available they probably sent you an e-mail telling you to make the change. That probably went unnoticed, and time went by. Finally last week, the mail admins cut off 25, and you could no longer send email.
Anyhow, a simple fix, you should be all set.
A day in the life of a computer repair tech 