We came across an issue where two WSS 3.0 servers were setup in a sharepoint farm (Contoso01 & Contoso02) and a load balanced web site/clustered web site was created (http://contoso/) successfully (uses a host header). They were using a hardware load balancer and not using Windows Network Load Balancing. Servers were running Windows Server 2008 (however that is not important).

When trying to create/deploy a Microsoft Dynamics AX 2009 Role Centers and Enterprise Portal site from the first node (Contoso01) of the cluster and using the load balanced website url, we get the following error:

The Web site http://Contoso/sites/DynamicsAx was not created correctly.
The remote server returned an error: (401) Unauthorized.
System.Net.WebException
   at System.Net.HttpWebRequest.GetResponse()
   at Microsoft.Dynamics.Framework.Portal.Deployment.EPFeatureReceiver.CreateAxSitesAndPages(SPWeb site)
   at Microsoft.Dynamics.Framework.Portal.Deployment.EPFeatureReceiver.ProvisionAxSite(SPWeb site)

As part of troubleshooting we had followed the advised given on creating the BackConnectionHostNames registry entry as per blog titled: Installing Dynamics AX 2009 Enterprise Portal on a web site that has Host Headers configured, however that still did not work.

The issue was that it was failing to copy the portal files from the AOT to the cluster servername. The cluster name, contoso resolves to the hardware load balancers ip address as you would expect. However it needs to copy the files to the actual cluster node.

To workaround the issue, we created a host entry on the first node, which mapped the cluster hostname, Contoso, to the local ip address of the node. So for example, if node 1, Contoso01, servers ip address was 192.168.0.1 and this was the ip address mapped to the http://contoso/ web site, then we created a hostname contoso mapped to this address.

Next we first deleted the partially created site collection due to the original failure. Then we were able to create an Enterprise portal successfully on http://contoso/ address.