If you notice that your email has stopped working on your iPhone, it is likely due to a problem with the stored incorrect IP address of the mail server on the device itself. To resolve this issue, you need to recreate the email account. You can do this as follows (replace "domena" with the name of your domain):
1. Settings > Mail, Contacts, Calendars
2. Add Account
3. Other
4. Add Mail Account
5. Name: Ime: Ime, Adress: yourname@domain, Password: password of the email account
6. Next
7. Tab POP
8. Incoming mail server
Host name: mail.domain
Username: yourname@domain
Password: password of the email account
9. Outgoing server
Host name: mail.domain
Username: yourname@domain
Password: password of the email account
10. Save (if after verification an error appears stating that the server cannot be verified, press Continue and wait)
11. Tap on SMTP mail.domain
12. Tap on Primary Server mail.domain
13. Enable SSL and set the port to 465 (leave username and password fields empty)
14. Tap Done and check if emails are being sent and received
If you are still unable to resolve the issue, please contact our customer support.