Issue
One of the users on my Heroku Team or Personal App is expecting to receive email notifications for a particular app. Other team members or app collaborators who have access to our app received the email notifications, but this specific user hasn't.
Resolution
The user needs to be a collaborator on the app or an admin on your team in order to receive email notifications about the application.
If the user that is not receiving emails is already on the list of app collaborators or team admins, that user may need to finish setting up their Heroku account. Once they log in successfully for the first time, emails should start to arrive.