This is the Postfix program at host blade1.mc.yu.edu.
I'm sorry to have to inform you that the message returned
below could not be delivered to one or more destinations.
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 message returned below.
The Postfix program
<[Only registered users see links. ].edu>: host ymail.yu.edu[18.104.22.168] said: 550
<[Only registered users see links. ].edu>: Recipient address rejected: User unknown in local
recipient table (in reply to RCPT TO command)