Username: [your email address]
Password: [yout password]
POP/IMAP Server: mail.[your domain]
SMTP Server: mail.[your domain] port 587

Example for assistenza@timix.it

Username: assistenza@timix.it
Password: *********************
POP/IMAP Server: mail.timix.it
SMTP Server: mail.timix.it porta 587

WARNING
Port 587!

If your mail client doesn’t have a specific port field, you’ll need to specify the SMTP address like this:
mail.timix.it:587