My site development was going fine until I started getting the message "Connection to database failed"  when trying to access website through webmatrix.  My webconfig connection string reads as follows:

<connectionStrings>

    <!-- Connection String for
SQL Server 2008/2012 Express -->

    <add name="SiteSqlServer" connectionString="Data
Source=.\SQLExpress;AttachDbFilename=|DataDirectory|Database.mdf;Integrated
Security=True;User Instance=True" providerName="System.Data.SqlClient" />

    <!-- Connection String for
SQL Server 2008/2012

    <add
name="SiteSqlServer"
connectionString="Server=(local);Database=DotNetNuke;uid=;pwd=;"
providerName="System.Data.SqlClient" /> 

    -->

  </connectionStrings>

  <appSettings>

    <!-- Connection String for
SQL Server 2008/2012 Express - kept for backwards compatability - legacy
modules   -->

    <add key="SiteSqlServer" value="Data
Source=.\SQLExpress;AttachDbFilename=|DataDirectory|Database.mdf;Integrated Security=True;User
Instance=True" />

    <!-- Connection String for
SQL Server 2008/2012 - kept for backwards compatability - legacy modules

    <add
key="SiteSqlServer"
value="Server=(local);Database=DotNetNuke;uid=;pwd=;"/>
Can anyone help?

Greetings from Florida.  I am using Microsoft Webmatrix for creating my DNN website.  That is the only tool I am using.  Thanks for your interest in my post.