Last week I wanted to test some new Windows Azure Servicebus functionality. So I started by creating a simple WCF service to host on the cloud. After configuring my service settings in the web.config, I started the service and was confronted with the following error message:
Hostname mynamespace.servicebus.appfabriclabs.com can't support more than 1 level subdomain.
It took me some time to figure out the root cause of the problem. I had created a namespace on http://portal.appfabriclabs.com. After checking with Fiddler what was going on I realized that although I was using the appfabriclabs environment, the authentication was still passing on to windows.net with the error message above as a consequence.
After creating a service namespace through https://appfabric.azure.com. the application ran successfully.