It may be that your notifications setting are disabled. To solve this problem, you must enable your notification settings.
- Sign in to the Unity Services Dashboard.
- Select the project for which you are not receiving notifications.
- in the navigation window, click Cloud Build and then click Notifications.
On the Notifications page, you can configure notifications through Webhooks, Slack, or email.
If you are having problems doing this yourself, please contact Support by creating a new ticket here.
There is a Forum post on this topic here.