As an alternative to setting up an ActiveSync connection as described here, you can also access https://owa.uni-wh.de/owa/?layout=tnarrow with your cell phone or tablet using your web browser.

You will then get a version of the webmail interface optimized for small displays, which directly supports some Outlook/Exchange features compared to ActiveSync, such as access to the configuration of automatic replies when you are away, the display of categories or the display of additional mailboxes, provided that you have included them in OWA as described here.

With this type of access, however, you will not receive any optical or acoustic notification from your cell phone when a new mail arrives. Therefore, it may also make sense to combine both methods - ActiveSync and the one described here.