can't send email

[MimiM]

have 16 messages that will not send.

The message could not be sent. The authentication setting might not be
correct for your outgoing e-mail [SMTP] server. For help solving this
problem, go to Help, search for "Troubleshoot Windows Mail", and read the
"I'm having problems sending e-mail" section. If you need help determining
the proper server settings, please contact your e-mail service provider.

The rejected e-mail address was '(e-mail address removed)'. Subject 'Fw: Just the
black keys', Account: 'pop-server.neo.rr.com', Server:
'smtp-server.neo.rr.com', Protocol: SMTP, Server Response: '550 Invalid
recipient: <[email protected]>', Port: 25, Secure(SSL): No, Server Error:
550, Error Number: 0x800CCC79

 

[PA Bear [MS MVP]]

Are you certain that '(e-mail address removed)' is the correct address?

Have you ever been able to send from this email account with those settings?

 

[Dave]

Are you connected to Roadrunner when this happens?

 

[Gary VanderMolen]

I also get the server error
550 5.1.1 - Invalid mailbox: (e-mail address removed)

The only reasonable conclusion is that the recipient closed his rr.com account.