Fiddler 4 Certificate error on Windows
<p>I am using Fiddler to monitor HTTPS traffic for our private project. After upgrading to Windows 10 and installing Fiddler, I am unable to create a root certificate. I tried using Both CertEnroll and MakeCert and both returned that they cannot create a root certificate:</p>

<blockquote>
  <p>09:53:54:2275 Fiddler.CertMaker> [C:\Program Files (x86)\Fiddler2\MakeCert.exe -r -ss my -n "CN=DO_NOT_TRUST_FiddlerRoot, O=DO_NOT_TRUST, OU=Created by <a href="http://www.fiddler2.com" rel="noreferrer">http://www.fiddler2.com</a>" -sky signature -eku 1.3.6.1.5.5.7.3.1 -h 1 -cy authority -a sha256 -m 132 -b 01/07/2015 ] Returned Error: Creation of the interception certificate failed.</p>
  
  <p>makecert.exe returned -1.</p>
  
  <p>Results from C:\Program Files (x86)\Fiddler2\MakeCert.exe -r -ss my -n "CN=DO_NOT_TRUST_FiddlerRoot, O=DO_NOT_TRUST, OU=Created by <a href="http://www.fiddler2.com" rel="noreferrer">http://www.fiddler2.com</a>" -sky signature -eku 1.3.6.1.5.5.7.3.1 -h 1 -cy authority -a sha256 -m 132 -b 01/07/2015</p>
  
  <p>Error: Can't create the key of the subject ('JoeSoft')
  Failed</p>
</blockquote>

<p>AND</p>

<blockquote>
  <p>09:43:37:0332 /Fiddler.CertMaker> Invoking CertEnroll for Subject: CN=DO_NOT_TRUST_FiddlerRoot, O=DO_NOT_TRUST, OU=Created by <a href="http://www.fiddler2.com" rel="noreferrer">http://www.fiddler2.com</a>; Thread's ApartmentState: MTA
  09:43:39:0853 !ERROR: Failed to generate Certificate using CertEnroll. System.Reflection.TargetInvocationException Exception has been thrown by the target of an invocation. &lt; CertEnroll::CX509PrivateKey::Create: The requested operation cannot be completed. The computer must be trusted for delegation and the current user account must be configured to allow delegation. 0x80090345 (-2146892987 SEC_E_DELEGATION_REQUIRED)</p>
</blockquote>

<p>Every time when changing the service I Reset All Certificates and/or Removed Interception Certificates. Also the key in <code>AppData/Roaming/Microsoft/Crypt/RSA/{LONG_ID}</code> is nowhere to be found (the folder is always empty).
After browsing through forums, I followed some instructions and downloaded the Bouncy Castle Certificate Maker (the one suggested for Android) and that one created 2 root certificates and added them to Windows so they will be trusted. After doing so, all my HTTPS traffic looked like HTTP with tunneling. When looking into that issue, I found that in Text view it said </p>

<blockquote>
  <p>"This is a CONNECT tunnel, through which encrypted HTTPS traffic flows.
  Fiddler's HTTPS Decryption feature is enabled, but this specific tunnel was configured not to be decrypted. Settings can be found inside Tools > Fiddler Options > HTTPS."</p>
</blockquote>

<p>AND the logger returned a few of the following:</p>

<blockquote>
  <p>"10:02:38:5419 !Certificate cache didn't find certificate for [server.com]. Returning null to thread #30. ___ 10:02:38:5419 fiddler.https> Failed to obtain certificate for server.com due to Certificate Maker returned null when asked for a certificate for server.com"</p>
  
  <p>"Failed to create certificate for server.com: The requested operation cannot be completed. The computer must be trusted for delegation and the current user account must be configured to allow delegation."</p>
</blockquote>

<p>In the properties of a tunneling connection, I found</p>

<blockquote>
  <p>"X-HTTPS-DECRYPTION-ERROR: Could not find or generate interception certificate."</p>
</blockquote>

<p>Do you have any solutions for me? I'd really appreciate it. Thank you! :)</p>