If a license key does not work immediately when you enter it, there is no need to panic. Please ensure that you have followed the product instructions.
With some Office and Windows products, you also have the option of activating your software over the phone. To do this, click on "back" in the installation window and select "activate by phone".
In a selection window at the top you now have to select your country and then call a free 0800 number. Now you can follow the instructions which the telephone activation computer reports to you.
If you need further support, please contact us by email at firstname.lastname@example.org or by phone at +49 3221 2292585 so that we can provide you with an exchange key. Please describe your problem in a few sentences and include a screenshot of the error message.