On the iPhone, tap Settings
Tap Mail, Contacts, Calendars.
Tap Add Account
… and choose Other.
Click Add Mail Account
Under Incoming Mail Server settings, enter the following:
- Host Name: mail.yourdomain.com
- User Name: your full email address
- Password: the password of your email address
Under Outgoing Mail Server, enter the following:
- Host Name: mail.yourdomain.com
- User Name: your full email address
- Password: the password of your email address
- Use SSL: Off
- Authentication: Password
- Server Port 25
Your device will now ask if you want to use SSL. Select No.
Tap Save and wait for your IMAP account information to verify.
Content retrieved from: https://support.appliedi.net/kb/a211/how-do-i-set-up-an-imap-account-on-my-iphone.aspx.