[Dovecot] quota.

[Mauro]

Hallo.
Sorry for may bad english.
I'm running dovecot 1.0.15 on a debian lenny system.
I've set quota plugin and, under section plugin, I've set:

quota = maildir
quota_rule = *:storage=50M
quota_rule2 = Trash:storage=10%%
quota_warning = storage=95%% /usr/local/bin/quota-warning.sh 95
quota_warning2 = storage=80%% /usr/local/bin/quota-warning.sh 80.
For some accounts the quota limit works well.
When I send mail I receive a rejected mail for quota exceeded.
For some other accounts it doesn'work despite they have passed the 50M
storage limit.
Why?