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

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