What do the security warning codes mean?

Firefox shows you a warning page about a potential security risk when you try to connect to a secure site but your connection is not secure.

This site is not secure message in Edge, Chrome or Firefox

Troubleshooting SSL/TLS Browser Errors and Warnings

HTTP Status Codes: What Your Website Errors Really Mean?

Homeland Security Advisory System - Wikipedia

Certificate Error

Revised, streamlined announcements address risks, decrease confusion - University of Mississippi Medical Center

Google Critical Security Alert: Scam or Not?

Error, Roblox Wiki

Color-Coded Threat Level Advisory Under Attack

How to Fix “Your Connection is Not Private” Error - Panda Security

An SSL Error Has Occurred – How to Fix Certificate Verification Error

Guide on How to Fix the 'Warning: Potential Security Risk Ahead' in Firefox

How to Fix NET::ERR_CERT_AUTHORITY_INVALID: 10 Methods

How to Remove Windows Defender Security Warning Scam

Emergency Alert System - Wikipedia