Untrusted domain error when using membership - asp.net

Question

I'm trying to develop an ASP.NET website which has registration and login functions. To do this, I'm using Membership by following this guide:
http://msdn.microsoft.com/en-us/library/ff648345.aspx
I've run Aspnet_regsql.exe and set up the database, and also changed by Web.config file to reflect this:
<connectionStrings>
<add name="MsSqlConnection" connectionString="Data Source=fostvm;Initial Catalog=db_74;User ID=user74;password=mypassword;Integrated Security=SSPI;" />
</connectionStrings>
<authentication mode="Forms">
<forms loginUrl="Account/Login.aspx"
protection="All"
timeout="30"
name="AppNameCookie"
path="/FormsAuth"
requireSSL="false"
slidingExpiration="true"
defaultUrl="default.aspx"
cookieless="UseCookies"
enableCrossAppRedirects="false" />
</authentication>
<authorization>
<deny users="?" />
<allow users="*" />
</authorization>
<membership defaultProvider="SqlProvider" userIsOnlineTimeWindow="15">
<providers>
<clear />
<add
name="SqlProvider"
type="System.Web.Security.SqlMembershipProvider"
connectionStringName="MsSqlConnection"
applicationName="WebSite10"
enablePasswordRetrieval="false"
enablePasswordReset="true"
requiresQuestionAndAnswer="true"
requiresUniqueEmail="true"
passwordFormat="Hashed" />
</providers>
</membership>
I don't get any errors while loading the log in or registration page, but when I try to log in with dummy account data I get this error thrown:
Login failed. The login is from an untrusted domain and cannot be used with Windows authentication.
I've Googled it and found loads of threads from different forums and blogs but no solutions have worked.
Is there any glaring error in my config that I've missed?
Thanks.

Answer 1

My guess would be, that in your connection string you have.
Data Source=fostvm;Initial Catalog=db_74;User ID=user74;password=mypassword;Integrated Security=SSPI;
And can someone correct me, that when you have Integrated Security=SSPI specified, the User ID and password are ignored and windows authentication will be used? In this case most likly it would be Application Pool account, or maybe even IUSR_Account, for anonymous access, which may not have permissions to your database.
So to sum it up - try to remove the Integrated Security=SSPI from connection string, or replace it with Integrated Security=false