It appears many Mail users are having authentication problems in which they are prompted for the username and password every time a message is sent (either manually ...

Verizon is one of the many Internet Service Providers that require you to authenticate when sending mail. The purpose of SMTP authentication is to reduce email spamming and abusive mailing behaviors.

When it works correctly, email can feel seamless. But a failure reveals its two separate components: one kind of server handles your mail app retrieving messages; another sends them out. These ...