title: How to resolve 'preflight is invalid (redirect)' or 'redirect is not allowed for a preflight request'
body: <p>I have followed this step to setup my server to enable CORS.
  <a href="https://docs.microsoft.com/en-us/aspnet/web-api/overview/security/enabling-cross-origin-requests-in-web-api" rel="noreferrer">https://docs.microsoft.com/en-us/aspnet/web-api/overview/security/enabling-cross-origin-requests-in-web-api</a></p>
  
  <p>But now in my browser dev console, I see this error message:</p>
  
  <blockquote>
    <p>XMLHttpRequest cannot load <a href="https://serveraddress/abc" rel="noreferrer">https://serveraddress/abc</a>. Response for
    preflight is invalid (redirect)</p>
  </blockquote>
  
  <p>Do you know what can I do to fix it?  I am making a CORS request in HTTPS. I think that is causing the 'preflight is invalid (redirect)' failure.  But I don't know why or what is redirecting the OPTIONS request.</p>
  
  <p>Thank you.</p>