[Dovecot] system_groups_user=%u seem not to be considered by deliver

Hi,

while trying to deliver a mail I got the following error:

Jun 20 21:57:09 shrike dovecot: lda(matthias): Error: user matthias: Initialization failed: Namespace 'shared.': stat(/home/sharedbox/Maildir) failed: Permission denied (euid=1014(matthias) egid=1022(scheff32) missing +x perm: /home/sharedbox, euid is not dir owner) Jun 20 21:57:09 shrike dovecot: lda(matthias): Fatal: Invalid user settings. Refer to server log for more information.

The shared mailbox works without any problems when I access it with imap.

Regards,

Matthias