ot: maildir has overdrawn his diskspace quota

[voytek at sbt.net.au]

I have Postfix/Dovecot with virtual domains, same setup unaltered since
server was set up quite a while ago

last month, added a new virtual domain, 'just like before'.

but, today noticed this in the queue/log 'overdrawn his diskspace quota'[1]:

user's Maildir cur has like  48,762,696 bytes (lot less than other users)

tried some searches, found similar probs, but, no solution as yet

any ideas ?

after physically removing some emails from this user's 'cur', I re-queued
'stuck' message, it was then accepted

# quota -g vmail
# quota -u vmail
#

[1]
# grep 719855FC42  /var/log/maillog

Mar  3 15:20:58 emu postfix/smtpd[18535]: 719855FC42:
client=mail-pa0-f51.google.com[209.85.220.51]

Mar  3 15:20:58 emu postfix/cleanup[18631]: 719855FC42:
message-id=<54f536ad.21da440a.6572.3c07 at mx.google.com>

Mar  3 15:21:01 emu postfix/qmgr[1906]: 719855FC42:
from=<dsome1 at gmail.com>, size=5487190, nrcpt=1 (queue active)

Mar  3 15:21:01 emu postfix/virtual[20248]: 719855FC42: to=<anna at tld.com>,
relay=virtual, delay=3.5, delays=3.4/0/0/0.08, dsn=4.2.2, status=deferred
(maildir delivery failed: Sorry, the user's maildir has overdrawn his
diskspace quota, please try again later.)

Mar  3 15:27:53 emu postfix/qmgr[1906]: 719855FC42:
from=<dsome1 at gmail.com>, size=5487190, nrcpt=1 (queue active)

Mar  3 15:27:53 emu postfix/virtual[23352]: 719855FC42: to=<anna at tld.com>,
relay=virtual, delay=415, delays=415/0.01/0/0.07, dsn=4.2.2,
status=deferred (maildir delivery failed: Sorry, the user's maildir has
overdrawn his diskspace quota, please try again later.)