Please use the following settings for your e-mail account:
IMAP Incoming Settings
Hostname: mail.yourdomain.com
Username: user@domain.com
Password:
Server Port: 143
SMTP Outgoing Settings
Hostname: mail.yourdomain.com
Username: user@domain.com
Password:
Server Port: 587
iOS IMAP Setup
1. Go to Settings > Mail, then tap Accounts.
2. Tap Add Account, then select "Other"
3. Enter your email address and password and server details.
4. Tap Next and wait for Mail to verify your account.
5. Deselect, Notes, Contacts, Calendar and tap Next.
6. Tap Save.
Syncing your IMAP folders on your iPhone - How to subscribe to folders
If you set up the IMAP mail account on your iPhone, you may not find the IMAP folders in your Inbox folder. If this is the case, you'll need to specify the IMAP path prefix.
You can enter in the IMAP path prefix by going to Settings > Mail > Account > Advanced > IMAP Path Prefix. Enter the word "INBOX" (use all caps) and save the setting. Now, your folders should appear as subfolders in the Inbox.
IOS
Go to Settings > Mail, then tap Accounts