[Samba] cli_rpc_pipe_open_schannel_with_creds: rpc_pipe_bind failed with error NT_STATUS_RPC_PROTOCOL_ERROR

[Meg]

dear samba community,

we have a big problem on joining a Samba 3.5.6 PDC.
Hopefully anyone has an idea/suggestion.

When trying to join with a Samba 4.2.10 or 4.3.9 we got the following
error on client site:

Failed to pull dcerpc auth: NT_STATUS_RPC_PROTOCOL_ERROR.
cli_rpc_pipe_open_schannel_with_key: rpc_pipe_bind failed with error
NT_STATUS_RPC_PROTOCOL_ERROR
libnet_join_ok: failed to open schannel session on netlogon pipe to
server rz-vm12 for domain RZ. Error was NT_STATUS_RPC_PROTOCOL_ERROR
Failed to join domain: failed to verify domain membership after joining:
An RPC protocol error occurred.

the following is logged by winbind:

[2016/05/03 15:00:22.939792,  0]
../source3/rpc_client/cli_pipe.c:1965(rpc_pipe_bind_step_one_done)
     Failed to pull dcerpc auth: NT_STATUS_RPC_PROTOCOL_ERROR.
[2016/05/03 15:00:22.939905,  0]
../source3/rpc_client/cli_pipe.c:3209(cli_rpc_pipe_open_schannel_with_key)
     cli_rpc_pipe_open_schannel_with_key: rpc_pipe_bind failed with error
NT_STATUS_RPC_PROTOCOL_ERROR

On serversite only the following is logged:

[2016/05/03 15:42:43.198619,  2] auth/auth.c:304(check_ntlm_password)
     check_ntlm_password:  authentication for user [MACHINENAME$] ->
[MACHINENAME$] -> [MACHINENAME$] succeeded
[2016/05/03 15:42:43.216510,  2] passdb/pdb_ldap.c:572(init_sam_from_ldap)
     init_sam_from_ldap: Entry found for user: rz-vm57$
[2016/05/03 15:42:43.219008,  2]
passdb/pdb_ldap.c:2446(init_group_from_ldap)
     init_group_from_ldap: Entry found for group: 200
[2016/05/03 15:42:43.219478,  2]
../libcli/auth/credentials.c:307(netlogon_creds_server_check_internal)
     credentials check failed
[2016/05/03 15:42:43.219523,  0]
rpc_server/srv_netlog_nt.c:714(_netr_ServerAuthenticate3)
     _netr_ServerAuthenticate3: netlogon_creds_server_check failed.
Rejecting auth request from client MACHINENAME machine account MACHINENAME$


Settings 4.2.10:

[global]
       workgroup = RZ
       server string = Samba Server Version %v
       security = DOMAIN
       client schannel = No
       client NTLMv2 auth = No
       log file = /var/log/samba/log.%m
       max log size = 500
       winbind nss info = rfc2307 template
       require strong key = No
       client ipc signing = if_required
       idmap config * : backend = tdb

Settings 4.3.9:

[global]
           workgroup = RZ
           server string = Samba Server Version %v
           security = DOMAIN
           log file = /var/log/samba/log.%m_%u_%S
           max log size = 1024
           client ipc signing = if_required
           idmap config * : backend = tdb
           cups options = raw

Settings 3.5.6:

[global]
           workgroup = RZ
           netbios name = RZ
           server string = SMBRZ Samba Server %v
           map to guest = Bad User
           passdb backend = ldapsam:ldap://***
           log level = 2
           log file = /opt/samba/log/smb.log
           max log size = 50000
           unix extensions = No
           domain logons = Yes
           os level = 99
           domain master = Yes
           ldap admin dn = ***
           ldap group suffix = ou=posix
           ldap machine suffix = ou=machines
           ldap suffix = ***
           ldap user suffix = ou=people
           usershare allow guests = Yes
           wide links = Yes

thx a lot,
meg