[asp.net] How to resolve "Server Error in '/' Application" error?

vs2017 just added in these lines to csproj.user file

    <IISExpressAnonymousAuthentication>enabled</IISExpressAnonymousAuthentication>
    <IISExpressWindowsAuthentication>enabled</IISExpressWindowsAuthentication>
    <IISExpressUseClassicPipelineMode>false</IISExpressUseClassicPipelineMode>

with these lines in Web.config

<compilation debug="true" targetFramework="4.5" />
<httpRuntime targetFramework="4.5" maxRequestLength="1048576" />
<identity impersonate="false" />
<authentication mode="Windows" />
<authorization>
  <allow users="yourNTusername" />
  <deny users="?" />
</authorization>

And it worked