I'm very frustrated:

my web.config in web.config reports:

--->

<configuration>

<customErrors>
    <system.web>
        <customErrors mode="Off"/>
    </system.web>

</customErrors>


  <!-- register local configuration handlers -->
  <configSections>
    <sectionGroup name="dotnetnuke">
      <!-- the requirePermission attribute will cause a syntax warning - please ignore - it is required for Medium Trust support-->
      <section name="data" requirePermission="false" type="DotNetNuke.Framework.Providers.ProviderConfigurationHandler, DotNetNuke" />
      <section name="logging" requirePermission="false" type="DotNetNuke.Framework.Providers.ProviderConfigurationHandler, DotNetNuke" />
...

-->

I've a dubt: probably my web.config is not read by server, the errors is "BEFORE"...

the errors is:

Server Error in '/' Application.

and, I suppose, the error is in "root" application.

Then the web.config is not read and... the error is before...

Thanks for Your patience.