title: I can't connect to AD by "net ads join"(winbind)
body: <p>I want to connect to Windows Active Directory from CentOS 7 with Samba, winbind.
  Samba is already running but Winbind is not errored by following error at log.winbindd.</p>
  
  <blockquote>
    <p>../source3/winbindd/winbindd_util.c:891(init_domain_list)</p>
    
    <p>Could not fetch our SID - did we join? </p>
  </blockquote>
  
  <p>I try "net -d 10 ads join -S dcserver -U poweruser" then get error log.
  what parameter is Invalid? what parameter ddidn't I write in my config?
  I don't know "dn" written in this log.</p>
  
  <pre><code>kerberos_kinit_password: as poweruser@DMNAME.OURCO.JP using [MEMORY:libnet_join_user_creds] as ccache and config [/var/lib/samba/lock/smb_krb5/krb5.conf.DMNAME]
  Starting GENSEC mechanism spnego
  Starting GENSEC submechanism gse_krb5
  gse_get_client_auth_token: Server principal not found
  SPNEGO(gse_krb5) creating NEG_TOKEN_INIT for ldap/dcserver failed (next[(null)]): NT_STATUS_INVALID_PARAMETER
  Failed to setup SPNEGO negTokenInit request: NT_STATUS_INVALID_PARAMETER
  kinit succeeded but ads_sasl_spnego_gensec_bind(KRB5) failed for ldap/dcserver with user[poweruser] realm[DMNAME.OURCO.JP]: An invalid parameter was passed to a service or function.
  ads_sasl_spnego_gensec_bind(KRB5) failed for ldap/dcserver with user[poweruser] realm=[DMNAME.OURCO.JP]: An invalid parameter was passed to a service or function.
  libnet_Join:
      libnet_JoinCtx: struct libnet_JoinCtx
          out: struct libnet_JoinCtx
              account_name             : 'MYCENTSV$'
              netbios_domain_name      : 'DMNAME'
              dns_domain_name          : 'dmname.OURCO.JP'
              forest_name              : 'dmname.OURCO.JP'
              dn                       : NULL
              domain_guid              : 4b8db2c2-43fd-4008-be4f-66ad75c21c2d
              domain_sid               : *
                  domain_sid               : S-1-5-21-1645522239-789336058-839522115
              modified_config          : 0x00 (0)
              error_string             : 'failed to connect to AD: An invalid parameter was passed to a service or function.'
              domain_is_ad             : 0x01 (1)
              set_encryption_types     : 0x00000000 (0)
              krb5_salt                : NULL
              result                   : WERR_NERR_DEFAULTJOINREQUIRED
  Failed to join domain: failed to connect to AD: An invalid parameter was passed to a service or function.
  return code = -1
  msg_dgm_ref_destructor: refs=(nil)
  </code></pre>