postfix-dovecot Auth USER lookup failed

[Timothy Murphy]

I'm running postfix + dovecot on my CentOS-7 home server.
When I send myself a message I get this error message in /var/log/maillog:
  Aug  9 12:59:57 alfred postfix/lmtp[31336]: B0D02220748:
    to=<tim at localhost.gayleard.eu>, orig_to=<tim at localhost>,
    relay=alfred.gayleard.eu[private/dovecot-lmtp],
    delay=475, delays=474/0.03/0.02/0.09, dsn=4.3.0,
    status=deferred (host alfred.gayleard.eu[private/dovecot-lmtp] said:
    451 4.3.0 <tim at localhost.gayleard.eu> Internal error occurred.
    Refer to server log for more information. (in reply to RCPT TO command))
and in /var/log/dovecot I read
  Aug 09 13:13:03 auth-worker(31472):
    Error: passwd(tim at localhost.gayleard.eu): getpwnam() failed:
    Address family not supported by protocol
  Aug 09 13:13:03 lmtp(31470): Error: user tim at localhost.gayleard.eu: Auth 
USER lookup failed

It seems that USER is set to tim at localhost.gayleard.eu rather than tim .

I am including the line
  mailbox_transport = lmtp:unix:private/dovecot-lmtp
in /etc/postfix/main.cf .
If I omit this line so that postfix sends email directly to ~/Maildir
I have no problem - except that spam is not being filtered.

I give the output of postconf -n below.

Any advice or enlightenment gratefully received.


Output of postconf -n
----------------------
[tim at alfred ~]$ cat /tmp/postconf 
alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
debug_peer_level = 2
debugger_command = PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin ddd 
$daemon_directory/$process_name $process_id & sleep 5
home_mailbox = Maildir/
html_directory = no
inet_interfaces = all
inet_protocols = all
mail_owner = postfix
mailbox_transport = lmtp:unix:private/dovecot-lmtp
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
mydomain = gayleard.eu
myhostname = alfred.gayleard.eu
mynetworks = 192.168.0.0/24, 127.0.0.0/8
myorigin = $mydomain
newaliases_path = /usr/bin/newaliases.postfix
queue_directory = /var/spool/postfix
readme_directory = /usr/share/doc/postfix-2.6.6/README_FILES
relay_domains =
relayhost = out.alice.it
sample_directory = /usr/share/doc/postfix-2.6.6/samples
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/password
smtp_sasl_security_options =
smtpd_milters = unix:/var/run/spamass-milter/postfix/sock
unknown_local_recipient_reject_code = 550
----------------------


-- 
Timothy Murphy  
e-mail: gayleard /at/ eircom.net
School of Mathematics, Trinity College, Dublin 2, Ireland