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Learn about the error codes SEC_ERROR_UNKNOWN_ISSUER MOZILLA_PKIX_ERROR_MITM_DETECTED and ERROR_SELF_SIGNED_CERT on HTTPS websites and how to troubleshoot.
Firefox issues an insecure password warning when a web page's login form is not secure and your information could be stolen.
Page that describes how Firefox detects captive portal networks.
Learn why you might see time-related errors on HTTPS websites and how you can troubleshoot these errors by correcting your system clock.