[Dovecot] In-site migration from /etc/passwd to LDAP

[Maykel Moya]

I'm doing in-site migration of accounts from /etc/passwd to an LDAP
directory. The migration should be progressive (not all users at the
same time).

I'm already able to check mail for accounts in /etc/passwd and accounts
in LDAP. 

The problem is with mail delivery. I'm using Postfix + Dovecot-LDA. This
is the error I get with every delivery

--
dovecot: Oct 03 00:16:09 Info: auth(default): master in: USER   1
moya    service=deliver
dovecot: Oct 03 00:16:09 Info: auth(default): ldap(moya): user search:
base=ou=users,dc=sld,dc=cu scope=subtree
filter=(&(objectClass=posixAccount)(uid=moya))
fields=sldMailbox,uidNumber
dovecot: Oct 03 00:16:09 Info: auth(default): master out: USER  1
moya    home=/srv/vmail/m/moya/ uid=29174       gid=101
deliver(moya): Oct 03 00:16:09 Fatal: setuid(29174) failed: Operation
not permitted
--

29174 is the uid for moya, is the same in /etc/passwd or in LDAP via
posixAccount class.

Any advise please?

Regards,
maykel