If the tab displays an error code instead of the requested site: Reason # 1: the time and date are incorrectly set
This guide explains how to troubleshoot this issue in Mozilla Firefox and when it appears. But in some cases, the error 'your connection is not secure' may appear due to browser problems and incorrect system settings, and not due to problems related to the protocol. Blocking access to the web resource in this case is carried out for security reasons to prevent the loss of personal data and the penetration of viruses into the system. If you see an error while establishing a secure connection in Firefox, it means that the browser has detected insufficient encryption level of the HTTPS protocol or its certificate is invalid.
