title: IIS HTTP Error 500.30 - ASP.NET Core app failed to start event viewer showing Newtonsoft.Json could not be loaded
body: <p>I had this app running for over a year on an IIS server and suddenly after a deploy (after a year) the server started to fail with the following message:</p>
  <blockquote>
  <p>HTTP Error 500.30 - ASP.NET Core app failed to start</p>
  </blockquote>
  <p>I checked the logs under <code>Event Viewer &gt; Windows Logs &gt; Application &gt; .NET Runtime</code> and it says:</p>
  <pre><code>Application: w3wp.exe
  CoreCLR Version: 5.0.521.16609
  .NET Version: 5.0.5
  Description: The process was terminated due to an unhandled exception.
  Exception Info: System.IO.FileNotFoundException: Could not load file or assembly 'Newtonsoft.Json, Version=13.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed'. The system cannot find the file specified.
  File name: 'Newtonsoft.Json, Version=13.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed'
     at SelectWiseAPI.Extensions.ObjectExtension.ToJsonIndented(Object obj)
     at SelectWiseAPI.Startup.ConfigureServices(IServiceCollection services) in C:\inetpub\wwwroot\selectwise-api\SelectWiseAPI\Startup.cs:line 40
  ...
  </code></pre>
  <p>I don't have any references to <code>13.0.0.0</code>, my packages are <code>13.0.1</code>.</p>
  <p>Why is it trying to look for a different version? How can I fix this or find more information about it?</p>