Cox SMTP Setting for iPhoneby Mike Venture
Outgoing email is sent through a Simple Mail Transfer Protocol server. The Mail app on your iPhone needs the correct Cox SMTP server set for you to be able to send email using your Cox email account. Your iPhone should have detected the settings automatically when you set up the account, but it may not have, or Cox may have changed the settings after you set up the account.
Tap the "Settings" icon.
Tap "Mail, Contacts, Calendars."
Tap your Cox account in the list of email accounts.
Verify the account is turned on at the top of the screen
Tap "Add Server."
Enter "smtp.cox.net" without quotation marks in the Host Name field. Enter your Cox email username and password.
Tap "Save." Your iPhone will verify the server, which may take several minutes.