Fiddler blocks all other websites

3 posts, 0 answers
  1. Sridhar
    Sridhar avatar
    2 posts
    Member since:
    Jan 2016

    Posted 13 Jan 2016 Link to this post

    I have installed Fiddler, and changed Tools -> Fiddler Options -> Https tab -> and checked "Capture HPPTS Connects" & "Decrypt HTTPS traffic".

    While the fiddler is running, if I open any other web site in IE / Chrome, I get an error saying

    "Certificate Error: Navigation Blocked"

    There is a problem with this website’s security certificate.
    The security certificate presented by this website is not secure.
    Security certificate problems may indicate an attempt to fool you or intercept any data you send to the server.

    If close the fiddler, I am able to access all the websites using IE / Chrome. Could you please tell me how to resolve this issue.

  2. Vanya Pavlova
    Vanya Pavlova avatar
    2019 posts

    Posted 14 Jan 2016 Link to this post

    Hello Sridhar,

    Looking at the description of your problem I suggest that there might be a problem with the security settings in a corporate-managed environment. A local Group Policy may block changes to the list of trusted root cerficates. 

    Another option would be a software have installed software that blocks configuration changes on your computer. 

    Can you try to have a look at Fiddler's Log tab and check for errors?

    Vanya Pavlova
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  3. EricLaw
    EricLaw avatar
    66 posts
    Member since:
    Oct 2012

    Posted 30 Jan 2016 in reply to Sridhar Link to this post

    The message in question indicates that your clients have not been configured to trust Fiddler's root certificates. When you first enabled decryption, you were prompted for permission to trust the roots. If you declined, you will need to change that decision using the Actions button on Fiddler's Tools > Fiddler Options > HTTPS tab.
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