[exim] Problem with vacation_replay (autoreplay) transport

Hello,

I set up router and transport for vacation message. Router seems to work
OK, however I'm facing strange problem with transport. Exim user is
"exim" and belongs to group "sysusers". Regular users are in a different
group. I run exim as root user: exim -bd -d -v ---- debug mode

here is the transport - very standard....

vacation_reply:
driver = autoreply
file = $home/vacation.msg
file_expand
from = Autoreply System <$original_local_part@$original_domain>
log = $home/vacation.log
once = $home/vacation.db
once_repeat = 7d
subject = ${if def:h_Subject: {Re:
${quote:${escape:${length_50:$h_Subject:}}} (autoreply)} {I am on
vacation} }
text = "\
Dear $h_from\n\n\
This is an automatic reply. Feel free to send additional\n\
mail, as only this one notice will be generated once every 7 days.\n\
The following is a prerecorded message, sent for
$original_local_part@$original_domain:\n\
====================================================\n\n\
"
to = $sender_address

and I got something like this from stdout:

27285 no previous message sent to userx@???
27286 exec /opt/exim-4.67/bin/exim -d=0xfbbd5cfd -t -oem -oi -f <>
-E1IQQ0Y-000760-DZ
27286 Exim version 4.67 uid=1001 gid=513 pid=27286 D=fbbd5cfd
Berkeley DB: Sleepycat Software: Berkeley DB 4.4.20: (February 24, 2006)
Support for: crypteq iconv() PAM OpenSSL
Lookups: lsearch wildlsearch nwildlsearch iplsearch dbm dbmnz ldap
ldapdn ldapm
Authenticators: cram_md5 dovecot plaintext spa
Routers: accept dnslookup ipliteral manualroute queryprogram redirect
Transports: appendfile autoreply pipe smtp
Fixed never_users: 0
Size of off_t: 8
27286 changed uid/gid: forcing real = effective
27286 uid=0 gid=513 pid=27286
27286 auxiliary group list: <none>
27286 seeking password data for user "root": cache not available
27286 getpwnam() succeeded uid=0 gid=0
27286 configuration file is /opt/exim-4.67/configure
27286 log selectors = 00000ffc 00212001
27286 cwd=/home/user1 8 args: /opt/exim-4.67/bin/exim -d=0xfbbd5cfd -t
-oem -oi -f <> -E1IQQ0Y-000760-DZ
exim: debugging permission denied

why debugging problems when it's run as uid=0 (root)? or maybe it's
not.... maybe it's run as user1?

27280 SMTP<< QUIT
27280 SMTP>> 221 mail.loca.pl closing connection
27280 LOG: smtp_connection MAIN
27280 SMTP connection from xxxxxxxxxxxx closed by QUIT
27280 search_tidyup called
27279 child 27280 ended: status=0x0
27279 0 SMTP accept processes now running
27279 Listening...
27285 vacation_reply transport succeeded
27285 search_tidyup called
27281 vacation_reply transport returned DEFER for userx@???
27281 added retry item for T:userx@??? errno=0 more_errno=0 flags=0
27281 post-process userx@??? (1)
27281 LOG: MAIN
27281 == userx@??? R=user_vacation T=vacation_reply defer (0):
Failed to send message from vacation_reply transport (1)


I found out that when I add "user = exim" to transport and change
/home/user directory provileges to 777 transport works great. But this
is not a solution. I want to keep /home/userx directory provileges on
700 level.

What I'm doing wrong? Could any please send me some hint what to change?

Best regards,
Marcin