LDAP 服务器的奇怪问题

我的 LDAP 生产服务器运行了 1 年没有任何问题，我在通过 pam_ldap 进行身份验证时突然收到密码失败错误。因此它显示以下错误消息，我能够使用 ldap 客户端实用程序（如 ldapsearch）进行身份验证，也可以通过一些java应用程序，

在客户端，我在 /var/log/secure 中收到以下错误消息

Failed password for [username] from xx.xx.xx.xx port 38473 ssh2
fatal: Access denied for user [username] by PAM account configuration

在 LDAP 服务器日志上。

=> access_allowed: read access denied by auth(=xd) 
send_search_entry: conn 1711 access to attribute userPassword, value #0 not allowed

LDAP 服务器上的 ACL 配置

access to attrs=userPassword
        by self write
        by anonymous auth
        by dn.base="cn=Manager,dc=example,dc=com" write
        by * none
access to attrs=shadowLastChange
        by self write
        by * read
access to *
        by self write
        by dn.base="cn=Manager,dc=example,dc=com" write
        by * read

pam_ldap (/etc/pam.d/system-auth) 配置 - 客户端

#%PAM-1.0
# This file is auto-generated.
# User changes will be destroyed the next time authconfig is run.
auth        required      pam_env.so
auth        sufficient    pam_ldap.so try_first_pass
auth        sufficient    pam_unix.so nullok use_first_pass
auth        requisite     pam_succeed_if.so uid >= 500 quiet
auth        required      pam_deny.so

account     required      pam_unix.so broken_shadow
account     sufficient    pam_localuser.so
account     sufficient    pam_succeed_if.so uid < 500 quiet
account     [default=bad success=ok user_unknown=ignore] pam_ldap.so
account     required      pam_permit.so

password    requisite     pam_cracklib.so try_first_pass retry=3 debug minclass=4 dcredit=-1 ucredit=-1 ocredit=-1 lcredit=0 minlen=8
password    sufficient    pam_unix.so md5 shadow nullok try_first_pass use_authtok
password    sufficient    pam_ldap.so use_authtok
password    required      pam_deny.so

session     optional      pam_keyinit.so revoke
session     required      pam_limits.so
session     optional      pam_mkhomedir.so skel=/etc/skel/ umask=0077
session     [success=1 default=ignore] pam_succeed_if.so service in crond quiet use_uid
session     required      pam_unix.so
session     optional      pam_ldap.so

奇怪的是，很长一段时间以来我都没有对服务器端或客户端进行任何更改。