qmail-ldap error message!!

[8823544]

Hi,everyone:
        While I have already set up my
qmail(with ldap patch) and Openldap server,
I send a mail to the mail server and have some
error in logfile,
"Temporary_error_in_qmail-qmqpc_(as_mail_forwarder)_(LDAP-ERR_#239)".
What dose the message mean?