The RPC Server is Unavailable for the Specified Computer... NLB Win 2K8 R2 Sp1... Error Code: 0x80070721 ?

Dear Sir,

I have one Domain Controller running Windows 2008 R2 SP1 and 4 RDS Servers running Win 2K8 R2 SP1 as well to serve 486 clients.
All servers are fully patched.

I joined 4 RDS Servers into NLB cluster with one VIP for failover in case one server goes down.

Network Core Switch: CISCO Catalyst 3560G...
Servers: HP Proliant DL 380 G7

In each RDS Server, I used 3 NICs configured as the following:
              * 1 NIC for Network Remote Management to manage the server remotely.
              * 2 NICs configured as a Networking Team using HP NCU for the NLB Cluster.

In the Core CISCO Switch, I used 2 ports interfaces as Port-Channel "Etherchannel-LACP" for each RDS Server to increase the bandwidth /2Gbps.
2 bundle ports connected to each RDS Server - NIC Teaming interface.

Clients and Serves are on the same network subnet...

First: I joined all RDS Servers into the NLB cluster and everything was working fine - All servers are CONVERGED...
I noticed delay when the client connect to the RDS session host... VIP address.
I opened "nlbmgr" to double check the cluster status and I found out the error message when it tries to connect to 2nd, 3rd, 4th RDS Server (RPC Server is unavailable)...

I removed/deleted the cluster and tried to created again but without success...
I am able to join 2 RDS Servers into NLB cluster, but when I add the 3rd or the forth server into the cluster, I receive below error:
[The RPC Server is Unavailable for the Specified Computer...  Error Code: 0x80070721]

Below IPs are configured on each RDS Server:  NLB (VIP):
      NIC1 Network Management:  - DNS: (Domain Controller) No GW.
      NIC2 NLB: - DNS: (Domain Controller) No GW.

     NIC1 Network Management:  - DNS: (Domain Controller) No GW.
     NIC2 NLB: - DNS: (Domain Controller) No GW.

     NIC1 Network Management:  - DNS: (Domain Controller) No GW.
     NIC2 NLB: - DNS: (Domain Controller) No GW.

     NIC1 Network Management:  - DNS: (Domain Controller) No GW.
     NIC2 NLB: - DNS: (Domain Controller) No GW.

Please I need help on how to resolve the RPC Server is unavailable.
I did the same above configuration in the past without any problem :(

Thank you.

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1.Check in Server manually in System Log you will find  Group Policy Process Aborted error no- 1053 Userenv
2.This is due to the server cannot communicate with the Domain DNS
3.Check your Group Policy Settings in the Domain
ISC-IT-AdminAuthor Commented:
Hello Shaik,

Thank you for the reply.
Yes, it's true... Please find attached screenshot for more information...

Log Name:      System
Source:        Microsoft-Windows-GroupPolicy
Date:          26-Dec-11 8:37:31 PM
Event ID:      1055
Task Category: None
Level:         Error
User:          SYSTEM
Computer:      RDS-03.XXXXXX.NET
The processing of Group Policy failed. Windows could not resolve the computer name. This could be caused by one of more of the following:
a) Name Resolution failure on the current domain controller.
b) Active Directory Replication Latency (an account created on another domain controller has not replicated to the current domain controller).

Could you please help me step by step on how to resolve this issue.

ISC-IT-AdminAuthor Commented:
Hello Shaik,

I noticed also, when I log in into one of a member domain server, it's like 10 minute to log in as well. Strange...
What is the exact problem.

This Server is connecting to the Domain Properly within a Specified Interval.
This Case what i did in my server was Try to restart the following the following Services Routing and Remote Access, Still u face problem dejoin the server from domain and delete the server name in active-directory ,Computers ,Computername and rejoin the server to the Domain .
Hope will solve ur problem.

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Windows Server 2008

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