http://blogs.msdn.com/harsh/archive/2007/03/21/single-signon-error-codes-and-what-they-mean.aspxError Code Meaning When Thrown Bubbled Behavior How To Overcome -2140993974 SSO is not configured Failure when SSO has not been setup via Central Administration Critical error logged in ULS with error code. If SSO is not configured then configure fromen-USCommunityServer 2.1 SP1 (Build: 61025.2)http://blogs.msdn.com/harsh/archive/2007/03/21/single-signon-error-codes-and-what-they-mean.aspx#1949694Mon, 26 Mar 2007 06:19:40 GMT91d46819-8472-40ad-a661-2c78acb4018c:1949694Microsoft SharePoint Products and Technologies Team Blog<p>Recommended Reading for March and April (click here for previous recommendations). Lots of useful content</p> http://blogs.msdn.com/harsh/archive/2007/03/21/single-signon-error-codes-and-what-they-mean.aspx#2096835Thu, 12 Apr 2007 10:47:39 GMT91d46819-8472-40ad-a661-2c78acb4018c:2096835Roberdan<p><a rel="nofollow" target="_new" href="http://msdn2.microsoft.com/en-us/library/ms566925.aspx">http://msdn2.microsoft.com/en-us/library/ms566925.aspx</a> <a rel="nofollow" target="_new" href="http://technet2.microsoft.com/Office/en-us/library/841080ca-3e3b-4dbc-a081-43c29c76b3551033.mspx?mfr=true">http://technet2.microsoft.com/Office/en-us/library/841080ca-3e3b-4dbc-a081-43c29c76b3551033.mspx?mfr=true</a></p>