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Distrust or Delete proxy CA certificate failed

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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

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
Attached screenshots

Modified by Walter

All Replies (1)

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Ciao, prova a vedere se questo paragrafo del nostro articolo di supporto ti può essere in qualche modo d'aiuto o metterti sulla strada giusta:

https://support.mozilla.org/it/kb/questa-connessione-non-sicura#w_mozilla-pkix-error-mitm-detected