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Solution ID : SO6284

Last Modified : 05/22/2018

Error "Could not verify this certificate because the the issuer is not trusted."

Problem

When  visiting the secured pages one of the following errors occured:

Error: "This certificate cannot be verified up to a trusted certification authority"

Error: "sec_error_unknown_issuer"

Error: "This certificate was signed by an untrusted issuer"

Cause

 
This error will occur if the issuer of the currently installed certificate is not present on the client software.

Solution

Thawte root certificates are installed on most browsers by default. If this error occurs after installing the Thawte issued certificate check the following:
  1. Verify that your Thawte certificate is installed correctly in your server:
    1. Check that the result shows the correct Common Name and Valid Dates.
    2. Your certificate should be issued by a Thawte Intermediate Certificate.
    3. The Intermediate Certificate should be installed in your server. If the installation checker present a "Missing Intermediate Certificate", you can download the correct Intermediate certificate from the link provided and install it in your server.

    4.  
    Note: Verify your installation using the Thawte Installation Checker  
     
  2. Certificate installed / referenced on the server is a self signed certificate:
    A self signed certificate will have the same issued to and issued by. Therefore, this is not a Thawte issued certificate. Make sure to download the Thawte certificate from your account: Note: For installation instructions please view this page: SO1498
     
  3. Check that the root certificate is not deleted from the client software:
    The root certificates will be installed in the Certfication Authority certificate stores in the browsers. For non browser client software, please contact your software vendor for the location of the Certification Authority store.

    Thawtes Root certificates can be downloaded from the following link: http://www.thawte.com/roots/ 
    For the Thawte Trial certificates the Thawte Trial Secure Server Root CA will need to be installed. To install the Trial Root Certificate in your browser, please see solution SO13734