I've changed on the logs the real user and domain to user@domain.
Postfix log:
warning: BB2A0514045: virtual_alias_maps map lookup problem for "user@domain"
complete Dovecot log from the moment of loging to logout:
Nov 08 16:04:15 auth(default): Info: client in: AUTH 1 PLAIN service=imap secured lip=::1 rip=::1 lport=143 rport=46435 resp=d3d3QHNlZHVjLTA3OTEuY2lkYWRhb3BnLnNwLmdvdi5icgB3d3dAc2VkdWMtMDc5MS5jaWRhZGFvcGcuc3AuZ292LmJyAGNwaWRUZXN0ZVJvb3Q=
Nov 08 16:04:15 auth-worker(default): Info: sql(user@domain,::1): query: SELECT password FROM mailbox WHERE username='www@seduc-0791.cidadaopg.sp.gov.br' AND active='1'
Nov 08 16:04:15 auth(default): Info: client out: OK 1 user=user@domain
Nov 08 16:04:15 auth(default): Info: master in: REQUEST 59 9340 1
Nov 08 16:04:15 auth-worker(default): Info: sql(user@domain,::1): SELECT CONCAT(mailbox.storagebasedirectory, '/', mailbox.storagenode, '/', mailbox.maildir) AS home, CONCAT('*:bytes=', mailbox.quota*1048576) AS quota_rule FROM mailbox,domain WHERE mailbox.username='user@domain' AND mailbox.domain='user@domain' AND mailbox.enableimapsecured=1 AND mailbox.domain=domain.domain AND domain.backupmx=0 AND domain.active=1 AND mailbox.active=1
Nov 08 16:04:15 auth(default): Info: master out: USER 59 user@domain home=/var/vmail/vmail1/domain/user quota_rule=*:bytes=104857600
Nov 08 16:04:15 IMAP(user@domain): Info: Loading modules from directory: /usr/lib/dovecot/modules/imap
Nov 08 16:04:15 IMAP(user@domain): Info: Module loaded: /usr/lib/dovecot/modules/imap/lib10_quota_plugin.so
Nov 08 16:04:15 IMAP(user@domain): Info: Module loaded: /usr/lib/dovecot/modules/imap/lib11_imap_quota_plugin.so
Nov 08 16:04:15 IMAP(user@domain): Info: Module loaded: /usr/lib/dovecot/modules/imap/lib20_autocreate_plugin.so
Nov 08 16:04:15 IMAP(user@domain): Info: Effective uid=1823, gid=1823, home=/var/vmail/vmail1/domain/user
Nov 08 16:04:15 IMAP(user@domain): Info: Quota root: name=user backend=dict args=:proxy::quotadict
Nov 08 16:04:15 IMAP(user@domain): Info: Quota rule: root=user mailbox=* bytes=104857600 messages=0
Nov 08 16:04:15 IMAP(user@domain): Info: Quota warning: bytes=89128960 (85%) messages=0 command=/usr/local/bin/dovecot-quota-warning.sh 85
Nov 08 16:04:15 IMAP(user@domain): Info: Quota warning: bytes=94371840 (90%) messages=0 command=/usr/local/bin/dovecot-quota-warning.sh 90
Nov 08 16:04:15 IMAP(user@domain): Info: Quota warning: bytes=99614720 (95%) messages=0 command=/usr/local/bin/dovecot-quota-warning.sh 95
Nov 08 16:04:15 IMAP(user@domain): Info: dict quota: user=user@domain, uri=proxy::quotadict, noenforcing=0
Nov 08 16:04:15 IMAP(user@domain): Info: Namespace: type=private, prefix=, sep=/, inbox=yes, hidden=no, list=yes, subscriptions=yes
Nov 08 16:04:15 IMAP(user@domain): Info: maildir: data=//var/vmail/vmail1/domain/user/Maildir/:INDEX=//var/vmail/vmail1/domain/user/Maildir/
Nov 08 16:04:15 IMAP(user@domain): Info: maildir++: root=//var/vmail/vmail1/domain/user/Maildir, index=, control=, inbox=//var/vmail/vmail1/domain/user/Maildir
Nov 08 16:04:15 IMAP(user@domain): Info: Namespace: type=shared, prefix=Shared/%u/, sep=/, inbox=no, hidden=no, list=children, subscriptions=yes
Nov 08 16:04:15 IMAP(user@domain): Info: shared: root=, index=, control=, inbox=
Nov 08 16:04:15 IMAP(user@domain): Info: Namespace : Using permissions from //var/vmail/vmail1/user@domain/user/Maildir: mode=0700 gid=-1
Nov 08 16:04:15 imap-login: Info: Login: user=<user@domain>, method=PLAIN, rip=::1, lip=::1, secured
Nov 08 16:04:15 IMAP(user@domain): Info: Disconnected: Logged out bytes=50/410
Nov 08 16:04:15 auth(default): Info: new auth connection: pid=9352