Bugzilla email notifications broken

Summary

Bugzilla email notifications are not working.

Steps to reproduce

Make a comment on a bug (e.g. https://bugs.eclipse.org/bugs/show_bug.cgi?id=580009) and the emails are not sent.

What is the current bug behavior?

No emails. For Bug 580009 I didn't get notification of its being created, nor of any of the updates. The last bugzilla email I received was "Fri, 20 May, 06:40 (6 days ago)". I am getting gerrit and mailing list emails.

What is the expected correct behavior?

Emails :-)

Relevant logs and/or screenshots

Here you can see that bugzilla thinks it sent email:

I asked William if he got the emails and I will report back if he did.