DDTP not working

[YOSHINO Yoshihito <yy.y.ja.jp@gmail.com>]

Hi,

DDTP (mail interface) is not working on ddtp2.debian.net.

The Exim server does not seem to recognize "ddtp2.debian.net":

$ nc ddtp2.debian.net smtp
220 ddtp.debian.net ESMTP Exim 4.80 Sun, 18 Sep 2016 01:06:22 +0000
HELO ddtp2.debian.net
250 ddtp.debian.net Hello *** [***.***.***.***]
MAIL FROM: foo@example.com
250 OK
RCPT TO: pdesc@ddtp2.debian.net
550 relay not permitted

Another error occurs when I connect to the server as if it were ddtp.debian.net:

$ nc ddtp2.debian.net smtp
220 ddtp.debian.net ESMTP Exim 4.80 Sun, 18 Sep 2016 01:07:03 +0000
HELO ddtp.debian.net
250 ddtp.debian.net Hello *** [***.***.***.***]
MAIL FROM: foo@example.com
250 OK
RCPT TO: pdesc@ddtp.debian.net
451 Temporary local problem - please try later


Thanks in advance,
-- 
YOSHINO Yoshihito <yy.y.ja.jp@gmail.com>