Hi Pascal,
Can you check these steps:
1,After maintaining the domain for email(For Exa- XYZ.Com) try for sending test email.
2. You need to maintain Mail id which is linked to your outlook. Under employee master>>Personal Data>> Private Contact Data.
3. Once you maintain email id ,then goto Home WC >> Subscribe to Task.
4.Then you will get email notification as per your selected task.
Hope this will be helpful.
Thanks,
Nitin