If you are having problems sending mail via mail.3wcomm.net on your Apple iOS device please check your SMTP Server settings. Under iOS version 10 these settings can be found under;
Settings / Mail / Accounts / (Select Account) / Account / Outgoing Mail Server - SMTP / Primary Server - mail.3wcomm.net
This settings screen should look like the one below (with your email address). Please confirm that the Password field is not blank and Authentication is set to Password.