Hi Dgoossens,
When we set up the AAD Connect, we need to input an admin account of Office 365. And
the alternative address (Technical contact email) of the admin account is used to receive AAD Connect error notification emails.
Usually, the notification delivery feature is enabled by default. It’s not feasible to manually disable/enable it. We suggest you change the alternative address to check the issue.
If the issue persists, please remove the tool and reinstall it. Then check if error notification emails are correctly delivered.
Thanks,
Brook