[TOS] [Infra] Action Required: POSSE Cohort ML broken!

[Sebastian Dziallas]

Recent emails to the posse-cohort-2011 email from both Mel and my
accounts returned a beautiful email with the subject "undelivered mail
returned to sender". I'm attaching its content below.

It'd be great if somebody could look into this; it's hurting our
ability to communicate with our attendees as a group.

Let me know if any more data would be helpful!

--Sebastian

---

This is the mail system at host whitealder.osuosl.org.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

                   The mail system

<posse-cohort-2011 at lists.teachingopensource.org>: host
    ash.osuosl.org[140.211.166.34] said: 550 5.1.1
    <posse-cohort-2011 at lists.teachingopensource.org>: Recipient address
    rejected: User unknown in virtual alias table (in reply to RCPT TO command)