I have mvc project to deploy on commercial Windows web hosting, not Azure, no cloud services, no containers. I try to manage access to connectionstring. I put in into webconfig file:

<configuration>
  <location path="." inheritInChildApplications="false">
    <system.webServer>
      <handlers>
        <add name="aspNetCore" path="*" verb="*" modules="AspNetCoreModuleV2" resourceType="Unspecified" />
      </handlers>
      <aspNetCore processPath="dotnet" arguments=".RealProject.dll" stdoutLogEnabled="false" stdoutLogFile=".logsstdout" hostingModel="inprocess" />
    </system.webServer>
  </location>
<connectionStrings>  
        <add name="MyWebconfigConnString" connectionString="Data Source=RealServer;Database=RealName;Uid=RealUser;Password=RealPsw;Encrypt=Optional; TrustServerCertificate=True;" />   
  </connectionStrings> 
</configuration>

The connection string itself works fine when accessed during development from appsettings.json. Now I want to access it from Program.cs to pass it to builder, so in production the connection string would be read from webconfig:

    builder.Services.AddDbContext<ApplicationDbContext>(options => 
options.UseSqlServer(builder.Configuration.GetConnectionString("MyWebconfigConnString")));

and I got stucked. Simply typing its name in builder’s method doesn’t work. Have I omitted something important between saving data in webconfig and using it in program.cs? Or is it my “connectionstring specific” mistake while trying to access it?