The remote server returned an error: (401) Unauthorized on L

Need urgent help on the matter, as we are 2 hours behind go-live.

We are now having a very weird issues for Sitefinity Load Balancing on AWS EC2 Instances. the error return (401) Unauthorized and 503 server unavailable. 

We have already tried to configured everything and step by step from this guide docs.sitefinity.com/administration-ensure-content-consistency-on-all-nodes

ELB URL : stadiumastro-prod-web-elb-1843221563.ap-southeast-1.elb.amazonaws.com
web 01 : 52.77.65.52
web 02 : 52.74.209.9
web 03 : 52.77.89.151

Also, if you are browsing the ELB URL, you will notice the site is loading extremely slow while browse for just one instance is acceptable. i'm not sure is this issue causing the Sitefinity  performance on ELB.

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Timestamp: 4/20/2016 5:13:22 AM

Message: HandlingInstanceID: a72538f8-a709-4720-ae23-36addc7ec898
An exception of type 'System.Exception' occurred and was caught.
----------------------------------------------------------------
04/20/2016 13:13:22
Type : System.Exception, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
Message : Error sending system message to URL:52.77.65.52/.../HandleMessages; HTTP method: PUT; Host: null
Source :
Help link :
Data : System.Collections.ListDictionaryInternal
TargetSite :
HResult : -2146233088
Stack Trace : The stack trace is unavailable.
Additional Info:

MachineName : SAPRODWEB02
TimeStamp : 4/20/2016 5:13:22 AM
FullName : Telerik.Sitefinity.Utilities, Version=8.2.5902.0, Culture=neutral, PublicKeyToken=b28c218413bdf563
AppDomainName : /LM/W3SVC/2/ROOT-2-131056003720150934
ThreadIdentity :
WindowsIdentity : IIS APPPOOL\SA
    Inner Exception
    ---------------
    Type : System.Net.WebException, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
    Message : The remote server returned an error: (401) Unauthorized.
    Source : System
    Help link :
    Status : ProtocolError
    Response : System.Net.HttpWebResponse
    Data : System.Collections.ListDictionaryInternal
    TargetSite : System.IAsyncResult BeginGetResponse(System.AsyncCallback, System.Object)
    HResult : -2146233079
    Stack Trace :    at System.Net.HttpWebRequest.BeginGetResponse(AsyncCallback callback, Object state)
       at Telerik.Sitefinity.LoadBalancing.WebServiceSystemMessageSender.WithExceptionHandling(String url, String httpMethod, String hostHeader, Action action)



Category: ErrorLog

Priority: 0

EventId: 9010

Severity: Warning

Title:Enterprise Library Exception Handling

Machine: SAPRODWEB02

App Domain: /LM/W3SVC/2/ROOT-2-131056003720150934

ProcessId: 4628

Process Name: c:\windows\system32\inetsrv\w3wp.exe

Thread Name: 52.77.65.52/.../HandleMessages-Thread-1

Win32 ThreadId:4944

Extended Properties:
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Hi Yau Gene,

Have you tried pinging the node servers from one another to see if they can communicate with each other?

Additionally have you configured the security as per this documentation article:

http://docs.sitefinity.com/administration-configure-security

Regards,
Pavel Benov
Telerik

I had a similar Problem. In my case the reason for the 401 error was that some files in the SitefinityWebApp folder were write protected.

Hi Arno,

Yes that also could be a potential cause. Thank you for sharing your experience with the community.

Regards,
Pavel Benov
Telerik

Hi there we are experiencing the same.  Can you say which folder(s) and file(s) needed to be writeable?