To configure the IST email service on your iPhone, just follow the instructions at:
https://support.apple.com/en-us/HT201729
And use:
- Email: firstname.lastname@ist.ac.at
- Server: owa.ist.ac.at
- Domain: IST
- Username: ISTUsername
- Password: ISTPassword
You can now choose to sync Mail, Contacts, Calendars, Reminders, and Notes.