Password change not working when pwdSafeModify: TRUE

After the setup of an OpenLDAP directory using PasswordPolicy overlay with the pwdSafeModify: TRUE, if I try to change an account password, it get: "LDAP: error 50 - Must supply old password to be changed as well as new one". So I switched to the first tab 'current password' and supplied the old password, the error was the same.