title: Blazor sub app 404 error after upgrade to Preview 6
body: <p>In Blazor Preview 5 (.Net Core Hosted), I have successfully configured the app as a sub app on the Asp.net Core site using:</p>
  
  <pre><code>app.UseRouting();
  
  app.UseEndpoints(endpoints =&gt;
  {
      endpoints.MapDefaultControllerRoute();
      endpoints.MapRazorPages();
  });
  
  app.UseMvcWithDefaultRoute();
  
  app.Map("/superadmin", child =&gt; { 
  child.UseBlazor&lt;BlazorCoreHosted.SuperAdmin.Startup&gt;(); });
  </code></pre>
  
  <p>I am now trying to upgrade to Preview 6, but when the app loads I get a 404 error "Failed to load resource: the server responded with a status of 404 (Not Found)"</p>
  
  <p>THe URL being looked for is - <a href="http://localhost:52112/superadmin/_framework/blazor.webassembly.js" rel="nofollow noreferrer">http://localhost:52112/superadmin/_framework/blazor.webassembly.js</a></p>
  
  <p>I have tried the instructions at the following link, and variations of the same, but can't get past the error. </p>
  
  <p><a href="https://devblogs.microsoft.com/aspnet/asp-net-core-and-blazor-updates-in-net-core-3-0-preview-6/" rel="nofollow noreferrer">https://devblogs.microsoft.com/aspnet/asp-net-core-and-blazor-updates-in-net-core-3-0-preview-6/</a></p>
  
  <p>Can anyone advise how to get past this error? </p>
  
  <p>Thanks </p>
  
  <p>Mark</p>