calendar emails being rejected by postfix

[Mark Berndt]

Hello,

I've set up a group user grouptest at myserver.  I'm connected to kolab 2.3 by 
toltec connector and outlook 2003.

At first my grouptest at myserver would happily accept calendar invitations but 
now it is not working.  I set up a new user, anothergroup at myserver and it 
works fine.  I've set both up according to doc3 and I have a kontact client 
for other testing.  The group users are set to reject if conflicts, but also 
fail on always accept.

I can send emails to grouptest at myserver and they pass through postfix and are 
collected by the client.

When  I have outlook generate a calendar invitation, postfix always fails with 
5.3.0 service unavailable

Jun 17 18:20:59 kolab <info> postfix/smtp[29137]: 6CA0E516221: 
to=<grouptest at myserver>, relay=127.0.0.1[127.0.0.1]:10024, delay=0.48, 
delays=0.06/0.04/0.02/0.36, dsn=2.0.0, status=sent (250 2.0.0 Ok: queued as 
D8DCF5161EB)
Jun 17 18:20:59 kolab <info> postfix/qmgr[26624]: 6CA0E516221: removed
Jun 17 18:21:00 kolab <info> postfix/pipe[29142]: D8DCF5161EB: 
to=<grouptest at myserver>, relay=kolabmailboxfilter, delay=0.54, 
delays=0.01/0.03/0/0.49, dsn=5.3.0, status=bounced (service unavailable)

When I send from kontact, I always get a grouptest declines meeting invitation 
message.

I've checked the ldap account details and they are the same for 
grouptest at myserver and anothergroup at myserver  


Has anyone seen this happen before?

Why does kolabmailboxfilter reject my outlook invitation email?

Why does the kontact invitation pass through ok but always be rejected?

Where do  I look for further information?

Thanks

Marko