How to debug email sending?
I have a user who is not recieving emails despite having set his email address and subscribed to notifications. His profile inbox shows the notifications reaching him. However he does not get any email. Most people who have complained before have been getting the emails, but they were getting spam filtered. However in his case I do not see the emails in the mail.log on the server.
How can I debug where the notifications are getting lost before getting to the email?
Edit: I've checked their subscriptions settings are all set to instant. They are sending selected tags. And they have several active tags selected on the home screen.
I don't see any reference to his email in /var/log/mail.log