samba - Dec 2007 - Why `net join --ipaddress --server' failed to join domain but `net join --workgroup' could?

$ cat /my/smb.conf
[global]
        netbios name = myname
        workgroup = myworkgroup
        server string = RIMA running %v
        security = domain
        wins server = 192.168.3.21

$ net join --configfile=/my/smb.conf --workgroup=myworkgroup
'--user=administrator%passwd'
Joined domain myworkgroup.

$ net join --configfile=/my/smb.conf
--ipaddress=192.168.3.21--server=servername
'--user=administrator%passwd'
[2007/12/18 02:51:38, 0] rpc_client/cli_netlogon.c:cli_nt_setup_creds(256)
  cli_nt_setup_creds: request challenge failed
[2007/12/18 02:51:39, 0] rpc_client/cli_netlogon.c:cli_nt_setup_creds(256)
  cli_nt_setup_creds: request challenge failed
[2007/12/18 02:51:39, 0] utils/net_rpc_join.c:net_rpc_join_newstyle(319)
  Error domain join verification (reused connection):
NT_STATUS_INVALID_COMPUTER_NAME
Unable to join domain myworkgroup.


What does NT_STATUS_INVALID_COMPUTER_NAME mean? Anything wrong?