Step 1: Add Exchange Account
Open the general settings.
Go to "Mail" and then to "Accounts".
Click on "Add Profile" or "Account hinzufügen".
Wählen Sie "Microsoft Exchange"
Step 2: Create an account
Enter your email address and then confirm by clicking on "Next".
Click on "manual configuration" or "Manuell konfigurieren".
Type in your password and choose "mailgate.th-ab.de" for Server.
For the domain you type in "ad" and go on with your username.
Click on "Done" or "Fertig".