dovecot - Feb 2014 - Dovecot / Postfix and the quota-status

Dovecot Version: 2.2.12
Postfix Version: 2.9.6

Hello

I've configured the quota-status service (socket and port).
When I call the service with shell, he replied

request=smtpd_access_policy
sender=sender at domain.tld
recipient=recipient at domain.tld
size=100000

action=552 5.2.2 Mailbox is full

In shell the service returns a 552 when the quota is exceeded, but when 
postfix call it, the service return alway DUNNO.

How it's possible to debug the quota-status for understand why to 
postfix the service return DUNNO and not 552 ?
The mailbox it's overquota already, all quota check with shell return 
the good reply (552).

Thank in advance for your help,

Nathan


=> Postfix trace INET Call
**************************
connect(21, {sa_family=AF_INET, sin_port=htons(12340), 
sin_addr=inet_addr("127.0.0.1")}, 16) = -1 EINPROGRESS (Operation now
in
progress)
poll([{fd=21, events=POLLOUT}], 1, 100000) = 1 ([{fd=21, 
revents=POLLOUT}])
getsockopt(21, SOL_SOCKET, SO_ERROR, [0], [4]) = 0
fcntl(21, F_GETFL)                      = 0x802 (flags 
O_RDWR|O_NONBLOCK)
fcntl(21, F_SETFL, O_RDWR)              = 0
fcntl(21, F_GETFD)                      = 0
fcntl(21, F_SETFD, FD_CLOEXEC)          = 0
epoll_ctl(11, EPOLL_CTL_ADD, 21, {EPOLLIN, {u32=21}}) = 0
poll([{fd=21, events=POLLIN}], 1, 0)    = 0 (Timeout)
poll([{fd=21, events=POLLOUT}], 1, 100000) = 1 ([{fd=21, 
revents=POLLOUT}])
write(21, "request=smtpd_access_policy\nprot"..., 518) = 518
poll([{fd=21, events=POLLIN}], 1, 100000) = 1 ([{fd=21, 
revents=POLLIN}])
read(21, "action=DUNNO\n\n", 4096)      = 14


=> Postfix trace SOCKET Call
****************************
connect(21, {sa_family=AF_FILE, path="private/quota-status"}, 110) = 0
fcntl(21, F_GETFL)                      = 0x802 (flags 
O_RDWR|O_NONBLOCK)
fcntl(21, F_SETFL, O_RDWR)              = 0
fcntl(21, F_GETFD)                      = 0
fcntl(21, F_SETFD, FD_CLOEXEC)          = 0
epoll_ctl(11, EPOLL_CTL_ADD, 21, {EPOLLIN, {u32=21}}) = 0
poll([{fd=21, events=POLLIN}], 1, 0)    = 0 (Timeout)
poll([{fd=21, events=POLLOUT}], 1, 100000) = 1 ([{fd=21, 
revents=POLLOUT}])
write(21, "request=smtpd_access_policy\nprot"..., 516) = 516
poll([{fd=21, events=POLLIN}], 1, 100000) = 1 ([{fd=21, 
revents=POLLIN}])
read(21, "action=DUNNO\n\n", 4096)      = 14