Hi LaraT, Is there a specific error code appears to you ?? is it " Your connection is not secured" error ?? could you please tell me what is your antivirus? if it is "Your connection is not secured" error you can take alook at this article and see if it is working [[How to troubleshoot security error codes on secure websites]]

Please explain the problem in detail. What happens? What is the exact error messages?

You can check the date and time and time zone in the clock on your computer: (double) click the clock icon on the Windows Taskbar. *https://support.mozilla.org/en-US/kb/what-does-your-connection-is-not-secure-mean *https://support.mozilla.org/en-US/kb/troubleshoot-time-errors-secure-websites *https://support.mozilla.org/en-US/kb/secure-connection-failed-error-message You can check if there is more detail available about the issuer of the certificate. *click the "Advanced" button show more detail *click the blue error text (SEC_ERROR_UNKNOWN_ISSUER) to show the certificate chain *click "Copy text to clipboard" and paste the base64 certificate chain text in a reply If clicking the blue error text doesn't provide the certificate chain then try these steps to inspect the certificate. *open the Servers tab in the Certificate Manager **Options/Preferences -> Privacy & Security<br>Certificates: View Certificates -> Servers: "Add Exception" *paste the URL of the website (https://xxx.xxx) in it's Location field Let Firefox retrieve the certificate -> "Get Certificate" *click the "View" button and inspect the certificate You can see detail like the issuer of the certificate and intermediate certificates in the Details tab. If you did refresh Firefox and created a new profile then try to copy cert9.db from the "Old Firefox Data" folder on the desktop to the current profile folder. *https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the <b>about:profiles</b> page. *Help -> Troubleshooting Information -> Profile Directory:<br>Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder *http://kb.mozillazine.org/Profile_folder_-_Firefox