[Exim] Strange result of LDAP lookup

I met a strange LDAP lookup problem: lookup is failed, but the `accept` statement is successful. The detailed info was shown at the bottom of page.

ENV:
exim: v 4.41 /w exiscan-patch

Please give me some hints.

Cut from /etc/exim/exim.conf

begin acl

acl_check_rcpt:
    accept  hosts         = :

    accept  local_parts   = postmaster
            domains       = +local_domains
            endpass

    accept  domains       = +staff_domains
            endpass

    accept  domains       = +local_domains
            endpass
            message       = ERR_MSG_NO_SUCH_RECIPIENT
            verify        = recipient

    accept  hosts         = +relay_from_hosts

    accept  authenticated = *

    deny    message       = relay not permitted

The output of `exim -d-all+acl+lookup -bd -oX 1025` is:
14409 Process 14409 is ready for new message
14409 using ACL "acl_check_rcpt"
14409 processing "accept"
14409 check hosts = :
14409 accept: condition test failed
14409 processing "accept"
14409 check local_parts = postmaster
14409 accept: condition test failed
14409 processing "accept"
14409 check domains = +staff_domains
14409 accept: condition test failed
14409 processing "accept"
14409 check domains = +local_domains
14409 check verify = recipient
14409 search_open: ldap "NULL"
14409 search_find: file="NULL"
14409   key="ldap:///dc=baoxian168,dc=com??sub? (&(| (mail=abcagadfasdfsdl@???) (mailAlternateAddress=abcagadfasdfsdl@???) ) (accountStatus=active))" partial=-1 affix=NULL starflags=0
14409 LRU list:
14409 internal_search_find: file="NULL"
14409   type=ldap key="ldap:///dc=baoxian168,dc=com??sub? (&(| (mail=abcagadfasdfsdl@???) (mailAlternateAddress=abcagadfasdfsdl@???) ) (accountStatus=active))"
14409 database lookup required for ldap:///dc=baoxian168,dc=com??sub? (&(| (mail=abcagadfasdfsdl@???) (mailAlternateAddress=abcagadfasdfsdl@???) ) (accountStatus=active))
14409 LDAP parameters: user=NULL pass=NULL size=0 time=0 connect=-1 dereference=0
14409 perform_ldap_search: ldap URL = "ldap:///dc=baoxian168,dc=com??sub? (&(| (mail=abcagadfasdfsdl@???) (mailAlternateAddress=abcagadfasdfsdl@???) ) (accountStatus=active))" server=127.0.0.1 port=0 sizelimit=0 timelimit=0 tcplimit=-1
14409 after ldap_url_parse: host=127.0.0.1 port=0
14409 ldap_initialize with URL ldap://127.0.0.1:389/
14409 initialized for LDAP (v3) server 127.0.0.1:389
14409 LDAP_OPT_X_TLS_TRY set
14409 binding with user=NULL password=NULL
14409 Start search
14409 search ended by ldap_result yielding 101
14409 ldap_parse_result yielded 0: Success
14409 LDAP search: no results
14409 lookup failed
14409 search_open: ldap "NULL"
14409   cached open
14409 search_find: file="NULL"
14409   key="ldap:///dc=baoxian168,dc=com??sub? (&(| (mail=abcagadfasdfsdl@???) (mailAlternateAddress=abcagadfasdfsdl@???) ) (accountStatus=active))" partial=-1 affix=NULL starflags=0
14409 LRU list:
14409 internal_search_find: file="NULL"
14409   type=ldap key="ldap:///dc=baoxian168,dc=com??sub? (&(| (mail=abcagadfasdfsdl@???) (mailAlternateAddress=abcagadfasdfsdl@???) ) (accountStatus=active))"
14409 cached data used for lookup of ldap:///dc=baoxian168,dc=com??sub? (&(| (mail=abcagadfasdfsdl@???) (mailAlternateAddress=abcagadfasdfsdl@???) ) (accountStatus=active))
14409 lookup failed
14409 ----------- end verify ------------
14409 accept: condition test succeeded