On Firefox 76.0.1 and higher, students connecting to HTTPS sites may see warning screens like the one shown below. 

This is because Firefox, by default, has stopped trusting the Windows Certificate Store starting with version 76.0.1, and instead consults with its own trusted root CA certificate list. Therefore, the Deledao certificate installed in the Windows system certificate store is not trusted. 

This affects all proxy products by all its vendors. This can be resolved by one of the following methods.

Change Firefox Setting in Browser

  1. Type “about:config” into the Firefox address bar. 
  2. Type “security.enterprise_roots.enabled”. 
  3. Change the value to “true”. 


Change Firefox Settings using GPO to Multiple Computers

Please follow the instructions below to deploy this configuration change using GPO. Note, this process requires that Firefox is installed in the default location on the client computers.

  1. Add the files ‘deledao.cfg’ and ‘local-settings.js’ to a network share using the file in the attachment. Ensure that the share has read permissions for ‘Domain Computers’.
  2. Create/Edit a group policy in Group Policy Management.
  3. Edit the settings in ‘Computer Configuration > Preferences > Windows Settings > Files’.
  4. Right-click and select ‘New File’.
  5. Point the ‘Source File’ to deledao.cfg on the Network Share.
  6. Point the ‘Destination’ file to be C:\Program Files\Mozilla Firefox\deledao.cfg and ‘Apply’.
  7. Repeat the above steps to copy 'deledao.cfg' to C:\Program Files (x86)\Mozilla Firefox\deledao.cfg.
  8. Repeat the above steps to copy ‘local-settings.js’ to C:\Program Files\Mozilla Firefox\defaults\pref\local-settings.js.
  9. Repeat the above steps to copy ‘local-settings.js’ to C:\Program Files (x86)\Mozilla Firefox\defaults\pref\local-settings.js.


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