I'm trying out using pop3 if i can send email out. I'm getting the following error below. However, I have no issues when I send emails using the web interface. it's only in pop and IMPA that i'm having this error (pop port is not blocked btw, and cleartext login is enabled). any ideas?
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 'firstname.lastname@example.org'. Subject 'test', Account: 'mailhost.domainb.com', Server: 'mailhost.domainb.com', Protocol: SMTP, Server Response: '554 <email@example.com>: Relay access denied', Port: 25, Secure(SSL): No, Server Error: 554, Error Number: 0x800CCC79