Our application is Identity provider and enabled sp init sso for a google iphone mobile application. We are using .Net form authentication , IIS 7.5. This flwo works perfectly across all devices and platforms and also works iwth iphone PagerDuty mobile app. The only problem is with iphone google doc mobile app. When SP init sso initiated from google doc iphone mobile app, IIS throws 404 error page for protected pages but public page displayed correctly. I spent many days with google search and tried out most of the solutions available but none of them helped to resolve thsi issue. now client needs to execute this flow daily but no solution. I understand that this may not be the most relavent forum but I already tried with server side help forums but nothing worked out so thought to put up here if any one may ahve experienced and can provide any suggestions. I appreciate any of your helps. Thanks.