Hello, I am once again having troubles with a setup of a samba 4 DC and a Windows Server 2008R2 DC. Replication between these two stopped a few days ago. Since then the logs on the samba server are flooded with: Failed to bind to uuid e3514235-4b06-11d1-ab04-xxxxxxxxxxxx for ncacn_ip_tcp:10.0.1.8[49155,seal,krb5,target_hostname=5b0a3412-16d8-4673-b0ef-xxxxxxxxxxxx._msdcs.my.domain,target_principal=GC/DC2008.my.domain/my.domain,abstract_syntax=e3514235-4b06-11d1-ab04-xxxxxxxxxxxx/0x00000004,localaddress=10.0.1.102] NT_STATUS_LOGON_FAILURE samba-tool drs showrepl shows: Default-First-Site-Name\SERVER DSA Options: 0x00000001 DSA object GUID: 32663ca8-8fd0-442f-8ee8-3be9e72ce3a2 DSA invocationId: 2a684553-b0ca-44fb-a4b8-6f4979c4c071 ==== INBOUND NEIGHBORS === DC=ForestDnsZones,DC=my,DC=domain Default-First-Site-Name\DC2008 via RPC DSA object GUID: 5b0a3412-16d8-4673-b0ef-xxxxxxxxxxxx Last attempt @ Thu Mar 22 11:42:28 2018 CET failed, result 1326 (WERR_LOGON_FAILURE) 2834 consecutive failure(s). Last success @ Mon Mar 12 15:05:14 2018 CET DC=DomainDnsZones,DC=my,DC=domain Default-First-Site-Name\DC2008 via RPC DSA object GUID: 5b0a3412-16d8-4673-b0ef-xxxxxxxxxxxx Last attempt @ Thu Mar 22 11:42:30 2018 CET failed, result 1326 (WERR_LOGON_FAILURE) 2838 consecutive failure(s). Last success @ Mon Mar 12 15:05:15 2018 CET DC=my,DC=domain Default-First-Site-Name\DC2008 via RPC DSA object GUID: 5b0a3412-16d8-4673-b0ef-xxxxxxxxxxxx Last attempt @ Thu Mar 22 11:42:34 2018 CET failed, result 1326 (WERR_LOGON_FAILURE) 2838 consecutive failure(s). Last success @ Mon Mar 12 15:05:17 2018 CET CN=Schema,CN=Configuration,DC=my,DC=domain Default-First-Site-Name\DC2008 via RPC DSA object GUID: 5b0a3412-16d8-4673-b0ef-xxxxxxxxxxxx Last attempt @ Thu Mar 22 11:42:35 2018 CET failed, result 1326 (WERR_LOGON_FAILURE) 2829 consecutive failure(s). Last success @ Mon Mar 12 15:05:16 2018 CET CN=Configuration,DC=my,DC=domain Default-First-Site-Name\DC2008 via RPC DSA object GUID: 5b0a3412-16d8-4673-b0ef-xxxxxxxxxxxx Last attempt @ Thu Mar 22 11:42:37 2018 CET failed, result 1326 (WERR_LOGON_FAILURE) 2834 consecutive failure(s). Last success @ Mon Mar 12 15:05:16 2018 CET ==== OUTBOUND NEIGHBORS === DC=ForestDnsZones,DC=my,DC=domain Default-First-Site-Name\DC2008 via RPC DSA object GUID: 5b0a3412-16d8-4673-b0ef-xxxxxxxxxxxx Last attempt @ Thu Mar 22 11:46:06 2018 CET failed, result 1326 (WERR_LOGON_FAILURE) 127005 consecutive failure(s). Last success @ Thu Feb 8 13:49:38 2018 CET DC=DomainDnsZones,DC=my,DC=domain Default-First-Site-Name\DC2008 via RPC DSA object GUID: 5b0a3412-16d8-4673-b0ef-xxxxxxxxxxxx Last attempt @ Thu Mar 22 11:45:51 2018 CET failed, result 1326 (WERR_LOGON_FAILURE) 125829 consecutive failure(s). Last success @ Mon Mar 12 13:55:53 2018 CET DC=my,DC=domain Default-First-Site-Name\DC2008 via RPC DSA object GUID: 5b0a3412-16d8-4673-b0ef-xxxxxxxxxxxx Last attempt @ Thu Mar 22 11:45:56 2018 CET failed, result 1326 (WERR_LOGON_FAILURE) 150527 consecutive failure(s). Last success @ Mon Mar 12 12:10:05 2018 CET CN=Schema,CN=Configuration,DC=my,DC=domain Default-First-Site-Name\DC2008 via RPC DSA object GUID: 5b0a3412-16d8-4673-b0ef-xxxxxxxxxxxx Last attempt @ Thu Mar 22 11:46:00 2018 CET failed, result 1326 (WERR_LOGON_FAILURE) 111139 consecutive failure(s). Last success @ Thu Mar 8 11:45:40 2018 CET CN=Configuration,DC=my,DC=domain Default-First-Site-Name\DC2008 via RPC DSA object GUID: 5b0a3412-16d8-4673-b0ef-xxxxxxxxxxxx Last attempt @ Thu Mar 22 11:46:04 2018 CET failed, result 1326 (WERR_LOGON_FAILURE) 104308 consecutive failure(s). Last success @ Mon Mar 12 14:10:15 2018 CET ==== KCC CONNECTION OBJECTS === Connection -- Connection name: 972cc207-61cd-4c8d-bc8a-d9ef94179c30 Enabled : TRUE Server DNS name : DC2008.my.domain Server DN name : CN=NTDS Settings,CN=DC2008,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=my,DC=domain TransportType: RPC options: 0x00000001 Warning: No NC replicated for Connection! Tried a manual replication with samba-tool drs replicate dc2008.my.domain server.my.domain "DC=my,DC=domain" and got: Failed to bind to uuid e3514235-4b06-11d1-ab04-xxxxxxxxxxxx for ncacn_ip_tcp:10.0.1.8[49155,seal,target_hostname=dc2008.my.domain,abstract_syntax=e3514235-4b06-11d1-ab04-xxxxxxxxxxxx/0x00000004,localaddress=10.0.1.102] NT_STATUS_LOGON_FAILURE ERROR(<class 'samba.drs_utils.drsException'>): DRS connection to dc2008.my.domain failed - drsException: DRS connection to dc2008.my.domain failed: (-1073741715, 'Logon failure') On the windows side, repadmin /syncall tells me "The target principal name is incorrect" I verified DNS records from both sides like describe here, all OK: https://wiki.samba.org/index.php/Verifying_and_Creating_a_DC_DNS_Record Any ideas? Thanks, Andreas