Here are the steps for Exchange, see if you missed anything
Follow these steps to setup your Exchange ActiveSync account your iOS device:
- Tap Settings > Mail, Contacts, Calendars > Add Account > Microsoft Exchange.
- Enter the information in the fields below, then hit Next:
- Your iOS device will now try to locate your Exchange Server. If necessary, you will need to enter your front-end Exchange Server's complete address in the Server field.
- Choose which content you would like to synchronize: Mail, Contacts, and Calendars. Tap Save when finished.
Note: To modify your exchange settings, Tap Settings > Mail, Contacts, Calendars, select your Exchange account, and tap Account Info.
Since we do not know how your exchange server is setup, the following information is what I can recommend you to look into:
Also, if your colleagues know how to setup it up, I do also recommend you to ask them first as well.