Adguard causes FireFox (55.0.3 64-bit) error: sec_error_unknown_issuer

Discussion in 'Technical Support (AdGuard for Windows)' started by Burkhard, Sep 26, 2017.

  1. Burkhard

    Burkhard New Member

    Joined:
    Sep 26, 2017
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    Since I updated my 64bit FireFox to the current version 55.0.3 it is blocking almost any site I try to visit using secure HTTPS. In addition, I'm running AVAST Internet Security. I disabled AVAST' s HTTPS-Scanning (an option of AVAST' s Web-Protection component) but without success. The FoxFire error disappeared not until I shut down the Adguard service and unloaded the Adguard executable completely!
    I added some online Adguard filters in the past without having problems at all. Must I check all of them now, or is this a known issue with Adguard's basic implementation when running FF 55.0.3 64bit?
    Any hints/help appreciated!
     
  2. Blaz

    Blaz Moderator & Translator Staff Member Moderator

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    Dec 21, 2014
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    Try reinstalling Adguard's SSL certificate.
     
  3. Boo Berry

    Boo Berry Moderator + Beta Tester Moderator

    Joined:
    May 30, 2012
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    Close Firefox, open Adguard's settings and go to the Network section and select Reinstall Certificate to reinstall the SSL certificate.
     
  4. Burkhard

    Burkhard New Member

    Joined:
    Sep 26, 2017
    Messages:
    2
    Some months ago reinstalling the certificate solved my problem (running on one of my elder Windows 7 workstations).
    Today I'm facing the same malfunction again on my current Lenovo ThinkPad T350 notebook running a 64bit Win10Pro installation. Again, I have AVAST Premier installed, as usual. All other browsers are running flawlessly(!), but my latest FireFox update does not.
    upload_2017-11-16_17-1-36.png

    Again, I am receiving this wired error message page telling me that the certificate for the sites I try to visit is not valid. Reinstalling Adguard's SSL certificat does not solve the problem.
    What more can I do (at the moment)?

    Many Thanx in advance!