Solved: RIA Services work on development server but fail on IIS

I'm building a prototype Silverlight 4 application using the Silverlight Business Application template as a starting point (I chose this template so that I could get ASP.NET forms authentication working "quickly").

My test app worked fine in the development web server (aka Casini if you are old enough to remember that), but it didn't work in IIS.

After some digging I found this post: Deploying Application built using RIA Services RC which solved my problem.  Solution: disable basic and integrated (aka: NT) auth.

Details from Saurabh's post:  "WCF (and by association RIA Services) has a limitation that it does not support MultipleAuthenticationSchemas enabled in IIS. So if you are using Forms Authentication in your application (if you built your application using the Business Application template, Forms Auth is the default there) you need to make sure that for the IIS VirtualRoot that hosts your WebApp Forms Auth is enabled. Forms Auth + Anonymous will also work fine but Forms Auth + Integrated Auth is not supported."