IIS prevent sub application inherit parent web.config

Add all config sections between the following tag

<location path="."  allowOverride="false" inheritInChildApplications="false">

</location>

Except <configSections> and <runtime>

Example:
<location path="."  allowOverride="false" inheritInChildApplications="false">

<connectionStrings>

      <add name="SiteSqlServer" connectionString="Data Source=SQL;Initial Catalog=moheportal;User ID=mmmm;Password=pppp" providerName="System.Data.SqlClient" />

    </connectionStrings>

    <appSettings>

</location>