Hi @Philipp Rössler ,
Welcome to our forum!
Based on my research, i found that when the following registries are deployed, those options in your image will be grayed out:
Please open the registry editor and check if the related four registries are displayed.
- Select Start, select Run, type regedit in the Open box, and then select OK.
- Locate and then select the registry subkey: Computer\HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\16.0\Outlook\preferences
- If the registries are displayed, right click it and delete it one by one.
(Note: Serious problems can occur if you modify the registry incorrectly. Before making changes, back up the registry to restore it in case something goes wrong.)
Hope to help you!
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.