[Mailman-Users] Subscription messages don't send out

[Hung Phan]

Hello,

We found that our Mailman doesn't send out the subscription confirmation messages for some lists but not all lists. The subscribe and smtp logs have the correspondence entries reflect the subscription and the confirmation message send out. In the exim log, we found this:

2010-12-02 12:26:12 1POFjI-0000ff-J2 <= listserv_test-bounces at mailman.domain H=localhost (localhost.localdomain) [127.0.0.1] P=esmtp S=2059 id=mailman.0.1291321571.2582.listserv_test at mailman.domain
2010-12-02 12:10:32 1POFU7-0000EJ-1n ** testuser-owner at canby.k12.or.us R=dnslookup T=remote_smtp: SMTP error from remote mail server after RCPT TO:<testuser-owner at canby.k12.or.us>: host canby.k12.or.us.s9a1.psmtp.com [74.125.148.10]: 550-5.1.1 The email account that you tried to reach does not exist. Please try\n550-5.1.1 double-checking the recipient's email address for typos or\n550-5.1.1 unnecessary spaces. Learn more at\n550 5.1.1 http://mail.google.com/support/bin/answer.py?answer=6596 u3si2832748ybe.73
2010-12-02 12:26:13 1POFjJ-0000fi-Ly <= <> R=1POFjI-0000ff-J2 U=exim P=local S=3394
2010-12-02 12:26:13 1POFjI-0000ff-J2 Completed
2010-12-02 12:26:14 1POFjJ-0000fi-Ly => listserv_test <listserv_test-bounces at mailman.domain> R=mailman_router T=mailman_transport
2010-12-02 12:26:14 1POFjJ-0000fi-Ly Completed

This testuser at canby.k12.or.us exists and able send/receive email without issue. 

Thank you for any advice