I can bypass the error by switching this flag to false, security.ssl.enable_ocsp_stapling. But it’s not a solution.
So it seems that the certificate of Keebtalk was renew today and now I have this issue on all my devices. Look like an error with OCSP stapling feature and the Keebtalk’s certificate.
Try clearing everything from your browser (all caches and browsing data) and restart it. I force https connections everywhere and I’m having no issues at all. I checked the certificate and it’s accurate.