Replication Error between DC and PDC after a reboot.

Question

Hi,
We have a very small  server environment and having one DC and one ADC.  Last week ADC got a sudden restart. After booting it shown one service failed error.  Since then the ADC  is not replicating with DC.  Giving below the diagnosis
results of Dcdiag and FSMO check.  
Domain Controller Diagnosis
Performing initial setup:
   Done gathering initial info.
Doing initial required tests
   Testing server: Default-First-Site-Name\DC
      Starting test: Connectivity
         ......................... DC passed test Connectivity
Doing primary tests
   Testing server: Default-First-Site-Name\DC
DNS Tests are running and not hung. Please wait a few minutes...
   Running partition tests on : ForestDnsZones
   Running partition tests on : DomainDnsZones
   Running partition tests on : Schema
   Running partition tests on : Configuration
   Running partition tests on : bannaridc
   Running enterprise tests on : bannaridc.com
      Starting test: DNS
         ......................... bannaridc.com passed test DNS
Domain Controller Diagnosis
Performing initial setup:
   * Verifying that the local machine backupdc, is a DC. 
   * Connecting to directory service on server backupdc.
   * Collecting site info.
   * Identifying all servers.
   * Identifying all NC cross-refs.
   * Found 2 DC(s). Testing 1 of them.
   Done gathering initial info.
Doing initial required tests
   Testing server: Default-First-Site-Name\BACKUPDC
      Starting test: Connectivity
         * Active Directory LDAP Services Check
         * Active Directory RPC Services Check
         ......................... BACKUPDC passed test Connectivity
Doing primary tests
   Testing server: Default-First-Site-Name\BACKUPDC
      Starting test: Replications
         * Replications Check
         [Replications Check,BACKUPDC] A recent replication attempt failed:
            From DC to BACKUPDC
            Naming Context: DC=ForestDnsZones,DC=bannaridc,DC=com
            The replication generated an error (1256):
            The remote system is not available. For information about network troubleshooting, see Windows Help.
            The failure occurred at 2014-05-15 12:29:41.
            The last success occurred at 2014-05-12 09:23:27.
            76 failures have occurred since the last success.
         REPLICATION LATENCY WARNING
         ERROR: Expected notification link is missing.
         Source DC
         Replication of new changes along this path will be delayed.
         This problem should self-correct on the next periodic sync.
         [Replications Check,BACKUPDC] A recent replication attempt failed:
            From DC to BACKUPDC
            Naming Context: DC=DomainDnsZones,DC=bannaridc,DC=com
            The replication generated an error (1256):
            The remote system is not available. For information about network troubleshooting, see Windows Help.
            The failure occurred at 2014-05-15 12:29:41.
            The last success occurred at 2014-05-12 09:33:40.
            76 failures have occurred since the last success.
         REPLICATION LATENCY WARNING
         ERROR: Expected notification link is missing.
         Source DC
         Replication of new changes along this path will be delayed.
         This problem should self-correct on the next periodic sync.
         [Replications Check,BACKUPDC] A recent replication attempt failed:
            From DC to BACKUPDC
            Naming Context: CN=Schema,CN=Configuration,DC=bannaridc,DC=com
            The replication generated an error (5):
            Access is denied.
            The failure occurred at 2014-05-15 12:29:41.
            The last success occurred at 2014-05-12 09:23:26.
            76 failures have occurred since the last success.
         [Replications Check,BACKUPDC] A recent replication attempt failed:
            From DC to BACKUPDC
            Naming Context: CN=Configuration,DC=bannaridc,DC=com
            The replication generated an error (5):
            Access is denied.
            The failure occurred at 2014-05-15 12:29:41.
            The last success occurred at 2014-05-12 09:23:26.
            76 failures have occurred since the last success.
         REPLICATION LATENCY WARNING
         ERROR: Expected notification link is missing.
         Source DC
         Replication of new changes along this path will be delayed.
         This problem should self-correct on the next periodic sync.
         [Replications Check,BACKUPDC] A recent replication attempt failed:
            From DC to BACKUPDC
            Naming Context: DC=bannaridc,DC=com
            The replication generated an error (5):
            Access is denied.
            The failure occurred at 2014-05-15 12:29:42.
            The last success occurred at 2014-05-12 09:42:25.
            95 failures have occurred since the last success.
         REPLICATION LATENCY WARNING
         ERROR: Expected notification link is missing.
         Source DC
         Replication of new changes along this path will be delayed.
         This problem should self-correct on the next periodic sync.
         * Replication Latency Check
         REPLICATION-RECEIVED LATENCY WARNING
         BACKUPDC:  Current time is 2014-05-15 13:24:11.
            DC=ForestDnsZones,DC=bannaridc,DC=com
               Last replication recieved from DC at 2014-05-12 09:23:27.
               Latency information for 2 entries in the vector were ignored.
                  2 were retired Invocations.  0 were either: read-only replicas and are not verifiably latent, or dc's no longer replicating this nc.  0 had no latency information (Win2K DC).  
            DC=DomainDnsZones,DC=bannaridc,DC=com
               Last replication recieved from DC at 2014-05-12 09:33:40.
               Latency information for 2 entries in the vector were ignored.
                  2 were retired Invocations.  0 were either: read-only replicas and are not verifiably latent, or dc's no longer replicating this nc.  0 had no latency information (Win2K DC).  
            CN=Schema,CN=Configuration,DC=bannaridc,DC=com
               Last replication recieved from DC at 2014-05-12 09:23:26.
               Latency information for 2 entries in the vector were ignored.
                  2 were retired Invocations.  0 were either: read-only replicas and are not verifiably latent, or dc's no longer replicating this nc.  0 had no latency information (Win2K DC).  
            CN=Configuration,DC=bannaridc,DC=com
               Last replication recieved from DC at 2014-05-12 09:23:26.
               Latency information for 2 entries in the vector were ignored.
                  2 were retired Invocations.  0 were either: read-only replicas and are not verifiably latent, or dc's no longer replicating this nc.  0 had no latency information (Win2K DC).  
            DC=bannaridc,DC=com
               Last replication recieved from DC at 2014-05-12 09:42:25.
               Latency information for 2 entries in the vector were ignored.
                  2 were retired Invocations.  0 were either: read-only replicas and are not verifiably latent, or dc's no longer replicating this nc.  0 had no latency information (Win2K DC).  
         * Replication Site Latency Check 
         ......................... BACKUPDC passed test Replications
      Test omitted by user request: Topology
      Test omitted by user request: CutoffServers
      Starting test: NCSecDesc
         * Security Permissions check for all NC's on DC BACKUPDC.
         * Security Permissions Check for
           DC=ForestDnsZones,DC=bannaridc,DC=com
            (NDNC,Version 2)
         * Security Permissions Check for
           DC=DomainDnsZones,DC=bannaridc,DC=com
            (NDNC,Version 2)
         * Security Permissions Check for
           CN=Schema,CN=Configuration,DC=bannaridc,DC=com
            (Schema,Version 2)
         * Security Permissions Check for
           CN=Configuration,DC=bannaridc,DC=com
            (Configuration,Version 2)
         * Security Permissions Check for
           DC=bannaridc,DC=com
            (Domain,Version 2)
         ......................... BACKUPDC passed test NCSecDesc
      Starting test: NetLogons
         * Network Logons Privileges Check
         Verified share \\BACKUPDC\netlogon
         Verified share \\BACKUPDC\sysvol
         ......................... BACKUPDC passed test NetLogons
      Starting test: Advertising
         The DC BACKUPDC is advertising itself as a DC and having a DS.
         The DC BACKUPDC is advertising as an LDAP server
         The DC BACKUPDC is advertising as having a writeable directory
         The DC BACKUPDC is advertising as a Key Distribution Center
         Warning: BACKUPDC is not advertising as a time server.
         ......................... BACKUPDC failed test Advertising
      Starting test: KnowsOfRoleHolders
         Role Schema Owner = CN=NTDS Settings,CN=DC,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=bannaridc,DC=com
         Role Domain Owner = CN=NTDS Settings,CN=DC,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=bannaridc,DC=com
         Role PDC Owner = CN=NTDS Settings,CN=DC,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=bannaridc,DC=com
         Role Rid Owner = CN=NTDS Settings,CN=DC,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=bannaridc,DC=com
         Role Infrastructure Update Owner = CN=NTDS Settings,CN=DC,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=bannaridc,DC=com
         ......................... BACKUPDC passed test KnowsOfRoleHolders
      Starting test: RidManager
         * Available RID Pool for the Domain is 3107 to 1073741823
         * DC.bannaridc.com is the RID Master
         * DsBind with RID Master was successful
         * rIDAllocationPool is 2607 to 3106
         * rIDPreviousAllocationPool is 2607 to 3106
         * rIDNextRID: 2771
         ......................... BACKUPDC passed test RidManager
      Starting test: MachineAccount
         Checking machine account for DC BACKUPDC on DC BACKUPDC.
         * SPN found :LDAP/backupdc.bannaridc.com/bannaridc.com
         * SPN found :LDAP/backupdc.bannaridc.com
         * SPN found :LDAP/BACKUPDC
         * SPN found :LDAP/backupdc.bannaridc.com/BANNARIDC
         * SPN found :LDAP/bcbf105f-e755-4c24-b846-01d447834480._msdcs.bannaridc.com
         * SPN found :E3514235-4B06-11D1-AB04-00C04FC2DCD2/bcbf105f-e755-4c24-b846-01d447834480/bannaridc.com
         * SPN found :HOST/backupdc.bannaridc.com/bannaridc.com
         * SPN found :HOST/backupdc.bannaridc.com
         * SPN found :HOST/BACKUPDC
         * SPN found :HOST/backupdc.bannaridc.com/BANNARIDC
         * SPN found :GC/backupdc.bannaridc.com/bannaridc.com
         ......................... BACKUPDC passed test MachineAccount
      Starting test: Services
         * Checking Service: Dnscache
         * Checking Service: NtFrs
         * Checking Service: IsmServ
         * Checking Service: kdc
         * Checking Service: SamSs
         * Checking Service: LanmanServer
         * Checking Service: LanmanWorkstation
         * Checking Service: RpcSs
         * Checking Service: w32time
         * Checking Service: NETLOGON
         ......................... BACKUPDC passed test Services
      Test omitted by user request: OutboundSecureChannels
      Starting test: ObjectsReplicated
         BACKUPDC is in domain DC=bannaridc,DC=com
         Checking for CN=BACKUPDC,OU=Domain Controllers,DC=bannaridc,DC=com in domain DC=bannaridc,DC=com on 1 servers
            Object is up-to-date on all servers.
         Checking for CN=NTDS Settings,CN=BACKUPDC,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=bannaridc,DC=com in domain CN=Configuration,DC=bannaridc,DC=com on 1 servers
            Object is up-to-date on all servers.
         ......................... BACKUPDC passed test ObjectsReplicated
      Starting test: frssysvol
         * The File Replication Service SYSVOL ready test 
         File Replication Service's SYSVOL is ready 
         ......................... BACKUPDC passed test frssysvol
      Starting test: frsevent
         * The File Replication Service Event log test 
         ......................... BACKUPDC passed test frsevent
      Starting test: kccevent
         * The KCC Event log test
         Found no KCC errors in Directory Service Event log in the last 15 minutes.
         ......................... BACKUPDC passed test kccevent
      Starting test: systemlog
         * The System Event log test
         An Error Event occured.  EventID: 0xC25A001D
            Time Generated: 05/15/2014   12:30:20
            (Event String could not be retrieved)
         An Error Event occured.  EventID: 0xC25A001D
            Time Generated: 05/15/2014   12:49:04
            (Event String could not be retrieved)
         An Error Event occured.  EventID: 0x40000004
            Time Generated: 05/15/2014   12:53:20
            Event String: The kerberos client received a
KRB_AP_ERR_MODIFIED error from the server
host/backupdc.bannaridc.com.  The target name
used was
LDAP/bcbf105f-e755-4c24-b846-01d447834480._msdcs.bannaridc.com.
 This indicates that the password used to encrypt
the kerberos service ticket is different than
that on the target server. Commonly, this is due
to identically named  machine accounts in the
target realm (BANNARIDC.COM), and the client
realm.   Please contact your system
administrator. 
         An Error Event occured.  EventID: 0xC25A001D
            Time Generated: 05/15/2014   13:12:19
            (Event String could not be retrieved)
         ......................... BACKUPDC failed test systemlog
      Test omitted by user request: VerifyReplicas
      Starting test: VerifyReferences
         The system object reference (serverReference)
         CN=BACKUPDC,OU=Domain Controllers,DC=bannaridc,DC=com and backlink on
         CN=BACKUPDC,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=bannaridc,DC=com
         are correct. 
         The system object reference (frsComputerReferenceBL)
         CN=BACKUPDC,CN=Domain System Volume (SYSVOL share),CN=File Replication Service,CN=System,DC=bannaridc,DC=com
         and backlink on CN=BACKUPDC,OU=Domain Controllers,DC=bannaridc,DC=com
         are correct. 
         The system object reference (serverReferenceBL)
         CN=BACKUPDC,CN=Domain System Volume (SYSVOL share),CN=File Replication Service,CN=System,DC=bannaridc,DC=com
         and backlink on
         CN=NTDS Settings,CN=BACKUPDC,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=bannaridc,DC=com
         are correct. 
         ......................... BACKUPDC passed test VerifyReferences
      Test omitted by user request: VerifyEnterpriseReferences
      Test omitted by user request: CheckSecurityError
   Running partition tests on : ForestDnsZones
      Starting test: CrossRefValidation
         ......................... ForestDnsZones passed test CrossRefValidation
      Starting test: CheckSDRefDom
         ......................... ForestDnsZones passed test CheckSDRefDom
   Running partition tests on : DomainDnsZones
      Starting test: CrossRefValidation
         ......................... DomainDnsZones passed test CrossRefValidation
      Starting test: CheckSDRefDom
         ......................... DomainDnsZones passed test CheckSDRefDom
   Running partition tests on : Schema
      Starting test: CrossRefValidation
         ......................... Schema passed test CrossRefValidation
      Starting test: CheckSDRefDom
         ......................... Schema passed test CheckSDRefDom
   Running partition tests on : Configuration
      Starting test: CrossRefValidation
         ......................... Configuration passed test CrossRefValidation
      Starting test: CheckSDRefDom
         ......................... Configuration passed test CheckSDRefDom
   Running partition tests on : bannaridc
      Starting test: CrossRefValidation
         ......................... bannaridc passed test CrossRefValidation
      Starting test: CheckSDRefDom
         ......................... bannaridc passed test CheckSDRefDom
   Running enterprise tests on : bannaridc.com
      Starting test: Intersite
         Skipping site Default-First-Site-Name, this site is outside the scope
         provided by the command line arguments provided. 
         ......................... bannaridc.com passed test Intersite
      Starting test: FsmoCheck
         GC Name: \\DC.bannaridc.com
         Locator Flags: 0xe00003fd
         PDC Name: \\DC.bannaridc.com
         Locator Flags: 0xe00003fd
         Time Server Name: \\DC.bannaridc.com
         Locator Flags: 0xe00003fd
         Preferred Time Server Name: \\DC.bannaridc.com
         Locator Flags: 0xe00003fd
         KDC Name: \\backupdc.bannaridc.com
         Locator Flags: 0xe00001b8
         ......................... bannaridc.com passed test FsmoCheck
      Test omitted by user request: DNS
      Test omitted by user request: DNS
Please help me to resolve this issue.
Regards,
suren

Answer 1

Hi suren,
Error 1256 is logged as the replication status per partition as a result of the destination DC cancelling the sync request from the source DC due to a connectivity failure previously encountered.
Please refer to the articles below to troubleshoot the issue:
Troubleshooting AD Replication error 1256: The remote system is not available.
http://support.microsoft.com/kb/2200187
Troubleshooting AD Replication error 5: Access is denied
http://support.microsoft.com/kb/2002013
Regards,
Mandy
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