Any help appreciated:
when sending mail in outlook 2016, the server responds with "550 5.1.0 sender rejected".
Below are the settings used.
Note: Incoming mail is working fine.
Account Type: POP or POP3
Incoming Mail Server: mail.twc.com
Incoming Server - POP3 port: 995
Outgoing Mail Server (SMTP): mail.twc.com
Outgoing Server - SMTP port: 587
Inbound & Outbound User Name: Enter full email address
Inbound & Outbound Password: Email Password (same as Web Mail)
SMTP Server Requires Authentication: Checked
I am using Outlook Express.
My incomming Port (POP3) is Port 110 not Port 995.
Otherwise, my settings are the same as yours and my incomming and outgoing eMail is working ok.