Existing shared mailbox ... does not exist

[Ruga]

# 2.2.26.0 (23d1de6): /etc/dovecot/dovecot.conf
auth_default_realm = example.com
auth_mechanisms = cram-md5
auth_realms = example.com
auth_socket_path = /var/run/dovecot/auth-userdb
auth_verbose = yes
auth_winbind_helper_path =
default_client_limit = 256
default_internal_user = _dovecot
default_login_user = _dovenull
first_valid_uid = 458
mail_access_groups = vmail
mail_cache_min_mail_count = 25
mail_gid = vmail
mail_location = maildir:/var/vmail/%d/%n
mail_plugins = " acl quota"
mail_privileged_group = vmail
mail_uid = vmail
mailbox_list_index = yes
namespace {
hidden = no
inbox = no
list = yes
location = maildir:/var/vmail/%d/shared:INDEXPVT=/var/vmail/%d/%n/shared
mailbox Junk {
auto = create
comment = Shared junk folder
special_use = \Junk
}
mailbox info {
auto = subscribe
special_use =
}
mailbox jobs {
auto = create
special_use =
}
mailbox news {
auto = create
special_use =
}
prefix = Shared/
separator = /
subscriptions = no
type = public
}
namespace inbox {
hidden = no
inbox = yes
list = yes
location =
mailbox Archive {
special_use = \Archive
}
mailbox Drafts {
special_use = \Drafts
}
mailbox Junk {
comment = SPAM
special_use = \Junk
}
mailbox Notes {
special_use =
}
mailbox Sent {
special_use = \Sent
}
mailbox Trash {
special_use = \Trash
}
mailbox virtual/Flagged {
comment = All my flagged messages
special_use = \Flagged
}
prefix =
separator = /
subscriptions = yes
type = private
}
passdb {
args = scheme=CRAM-MD5 username_format=%n@%d /domains/%d/etc/mail/passdb
driver = passwd-file
}
plugin {
acl = vfile:/etc/dovecot/dovecot-acl.conf:cache_secs=300
acl_shared_dict = file:/var/vmail/%d/shared-mailboxes.db
quota = maildir:User quota:ns=
quota2 = maildir:Shared quota:ns=Shared/
quota_exceeded_message = Quota exceeded.
quota_rule = *:storage=0
quota_rule2 = Junk:storage=+100M
quota_rule3 = Trash:storage=+100M
}
protocols = imap
quota_full_tempfail = yes
service auth-worker {
user = $default_internal_user
}
service auth {
client_limit = 300
unix_listener /var/spool/postfix/private/auth {
group = postfix
mode = 0660
user = postfix
}
}
service dict {
unix_listener dict {
mode = 0600
user = vmail
}
}
service imap-login {
inet_listener imap {
port = 0
}
inet_listener imaps {
port = 993
ssl = yes
}
service_count = 1
}
userdb {
args = uid=vmail gid=vmail home=/var/vmail/%d/%n
driver = static
override_fields = home=/var/vmail/%d/%n mail=maildir:/var/vmail/%d/%n
}
protocol imap {
mail_plugins = " acl quota imap_acl imap_quota"
}