WCF RIA Service Issue

Question

I have a Silverlight app with WCF Ria services. I'm getting this error when I have Windows Auth and Anonymous Auth enabled within IIS whenever a service method is called:

System.InvalidOperationException: IIS specified authentication schemes 'IntegratedWindowsAuthentication, Anonymous', but the binding only supports specification of exactly one authentication scheme. Valid authentication schemes are Digest, Negotiate, NTLM, Basic, or Anonymous. Change the IIS settings so that only a single authentication scheme is used.

The http result is a 500 error.

So, I disabled Anonymous auth and figured that it would be fixed. However, now anytime I try to hit a web service, I get prompted for my credentials (404 responses) and I still can't access the service after entering them.

Anyone ideas how to fix? I've seen a bunch of articles online about similiar issues, and have tried various configurations with no luck yet.

Answer 1

After trying many different things, a light bulb went off and I realized a part of the issue. Somewhere along the line over the past hours trying to try different configurations, and getting credential challenges, my windows account was locked. I got the account unlocked, and then tried making some configuration changes again. The issue was that for the Windows Authentication providers, "Negotiate" was above "NTLM" in provider order. I noticed through fiddler that authorization was attempting to use "Negotiate" rather than NTLM and that's when I figured to try this next. Now the service calls work as configured below: