Authentication only for one page

[sssor1]

Hi everyone,

The error:

It is an error to use a section registered as allowDefinition='MachineToApplication' beyond application level. This error can be caused by a virtual directory not being configured as an application in IIS.

what I'm doing:

I need to enable forms authentication for only one of my pages.

so I made an application under my project using IIS and enabled its forms Authentication. The application contains the page that requires user to log in and a web.config. Below is the code of web.config under the application.

<?xml version="1.0"?>
<configuration>
    <appSettings/>
    <connectionStrings/>
    <system.web>
      
      <authentication mode="Forms">
        <forms loginUrl="login.aspx" protection="All" timeout="60" />
      </authentication>

      <machineKey validationKey="AutoGenerate" decryptionKey="AutoGenerate" validation="SHA1" />

      <authorization>
        <deny users="?" />
      </authorization>
    </system.web>
</configuration>

I can't move these codes to the main web.config of the project since in that case all the pages will require log-in.

I will be grateful of any help.