Your SMTP access is not authenticating, probably because you set it
up (by default) to authenticate with the POP credentials.
I notice you named the account mail.mac.com, which is probably also
the name of the incoming mail server. Under Tools, Accounts, select
that account, Properties, Servers, the box for "My server requires
authentication" is probably checked, which causes your mac.com
credentials to be presented to smtp.vzwmail.net, and that's not valid.
Go back to that screen and click the 'Settings' button that is near the
bottom. Then select "Log on using", then enter your Verizon
username and password. That username is typically
[10-digit phone number]@vzwmail.net. Click OK. Try sending.
Gary VanderMolen, MS-MVP (Mail)
"K9Kel" <firstname.lastname@example.org> wrote in message news:email@example.com...
> I'm trying to help my husband with his mail because I'm a mac user. Out
> of the blue the infamous pop up windows mail security box is asking for
> user name and password. It has been entered over and over. Rebooted,
> created new email account, verified username and password with server.
> No avail. Still the pop up box appears and no outgoing mail is allowed.
> It is mac mail address and verizon but has worked perfectly for months.
> Until today..... Below is the error message: Thanks in
> advance for any help!
> Subject' Re: Dwight Group', Account: 'mail.mac.com',
> Server:'smtp.vzwmail.net', Protocol: SMTP, Port 25, Secure(SSL):No,
> Error Number: 0x800ccc17