[Dovecot] "Can't sync delivery mail"

[Rich Winkel]

Dovecot 1.0.3
Deliver is saying this on two specific emails.  Other emails to these 2
users are going through fine.  Looking at the mail headers the only
thing questionable I see is:
From: "AMS Publication Division"@ams.org
Is this the problem?

# 1.0.3: /usr/local/etc/dovecot.conf
base_dir: /var/run/dovecot/
protocols: imap pop3
listen(default): *:143
listen(imap): *:143
listen(pop3): *:110
ssl_disable: yes
shutdown_clients: no
login_dir: /var/run/dovecot/login
login_executable(default): /usr/local/libexec/dovecot/imap-login
login_executable(imap): /usr/local/libexec/dovecot/imap-login
login_executable(pop3): /usr/local/libexec/dovecot/pop3-login
login_greeting_capability(default): yes
login_greeting_capability(imap): yes
login_greeting_capability(pop3): no
first_valid_uid: 100
mail_extra_groups: mail
mail_location: mbox:~/mail:INBOX=/var/mail/%u:INDEX=/var/spool/dovecot_indexes/%u
lock_method: flock
mbox_read_locks: flock
mbox_write_locks: flock
mail_executable(default): /usr/local/libexec/dovecot/imap
mail_executable(imap): /usr/local/libexec/dovecot/imap
mail_executable(pop3): /usr/local/libexec/dovecot/pop3
mail_plugin_dir(default): /usr/local/lib/dovecot/imap
mail_plugin_dir(imap): /usr/local/lib/dovecot/imap
mail_plugin_dir(pop3): /usr/local/lib/dovecot/pop3
pop3_uidl_format(default): 
pop3_uidl_format(imap): 
pop3_uidl_format(pop3): %08Xu%08Xv
pop3_client_workarounds(default): 
pop3_client_workarounds(imap): 
pop3_client_workarounds(pop3): outlook-no-nuls oe-ns-eoh
auth default:
  passdb:
    driver: pam
  userdb:
    driver: passwd
  socket:
    type: listen
    client:
      path: /var/run/dovecot/auth-client
      mode: 432
    master:
      path: /var/run/dovecot/auth-master
      mode: 432
      user: dovecot
      group: dovecot