Try to rename the cert8.db file in the Firefox profile folder to cert8.db.old or delete the cert8.db file to remove intermediate certificates that Firefox has stored.<br /> If you have user certificates that you want to keep then export those certificates to a .cer file before removing the cert8.db file.<br /> If that helped to solve the problem then you can remove the renamed cert8.db.old file.<br /> Otherwise you can rename (or copy) the cert8.db.old file to cert8.db to restore the previous intermediate certificates.<br /> Firefox will automatically store intermediate certificates when you visit websites that send such a certificate.<br /> You can use this button to go to the Firefox profile folder: *Help > Troubleshooting Information > Profile Directory: Open Containing Folder *Help -> Probleemoplossingsinformatie -> Profielmap -> Bijbehorende map openen ---- *http://kb.mozillazine.org/Profile_folder_-_Firefox