Please proceed as follows if you want to deactivate an existing forwarding in the Horde webmail system:
Forgot your password?
Please follow our passwort reset instruction.
Forgot your password and your Uni-ID?
Please contact our support team by calling +49 621 181–2000 or sending an e-mail to itsupport. We are happy to help you. uni-mannheim.de
In the menu, open “webmail” and click “filter” (sometimes you need to click on “filter” again so that you see the following dialog).
Here you can see the address to which your incoming emails will be sent. Now click on “Save and Disable” to remove the forwarding.