我按照本指南使用 LDAP 设置 Kerberos。我已遵循所有步骤。但是当我运行 kadmin.local 时，它会退出并显示以下错误：
以主要 root 身份进行身份验证/[电子邮件保护]用密码。
kadmin.local：无法将“cn=admin,dc=example,dc=com”绑定到 LDAP 服务器“ldaps://”：初始化 kadmin.local 接口时无法联系 LDAP 服务器
-- Subject: Unit krb5-kdc.service has begun start-up
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- Unit krb5-kdc.service has begun starting up.
Jan 02 06:19:12 ubuntu-512mb-blr1-01 systemd[1]: Starting Kerberos 5 Key Distribution Center...
-- Subject: Unit krb5-kdc.service has begun start-up
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- Unit krb5-kdc.service has begun starting up.
Jan 02 06:19:12 ubuntu-512mb-blr1-01 krb5kdc[17707]: Cannot bind to LDAP server 'ldaps://' as 'cn=admin,dc=example,dc=com': Can't contact LDAP server
Jan 02 06:19:12 ubuntu-512mb-blr1-01 krb5kdc[17707]: krb5kdc: cannot initialize realm EXAMPLE.COM - see log file for details
Jan 02 06:19:12 ubuntu-512mb-blr1-01 systemd[1]: krb5-kdc.service: Control process exited, code=exited status=1
Jan 02 06:19:12 ubuntu-512mb-blr1-01 sudo[17678]: pam_unix(sudo:session): session closed for user root
Jan 02 06:19:12 ubuntu-512mb-blr1-01 systemd[1]: Failed to start Kerberos 5 Key Distribution Center.
-- Subject: Unit krb5-kdc.service has failed
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- Unit krb5-kdc.service has failed.
--
-- The result is failed.
Jan 02 06:19:12 ubuntu-512mb-blr1-01 systemd[1]: krb5-kdc.service: Unit entered failed state.
Jan 02 06:19:12 ubuntu-512mb-blr1-01 systemd[1]: krb5-kdc.service: Failed with result 'exit-code'.