Hey folks, i need to delete an old custom CA certificate from Firefox due to expiration date and replace it with the new one. Our company uses a proxy server with its own CA certificate. I did this kind of tasks several time in the past without any issue at all but now it seems to be different. I am able to distrust or delete it from Certificate panel but in effect when i try to browse without any valid proxy certificate, for instance to google site, i get the error: MOZILLA_PKIX_ERROR_MITM_DETECTED and when i go to check certificates i find both google cert and old proxy cert. I tried to uninstall firefox and clean Mozilla's %appdata% folders in Local, Localraw and Roaming without any success. Is there anything about certificate saved on win registry or some other place? Any tips are welcome