Troubleshooting: how to fix certificate and HTTPS errors?

Security certificate and HTTPS protocol errors when visiting websites can occur for a variety of reasons, ranging from a trivial system clock failure on your computer to serious network attacks or problems on the resource's side. The practice of quick diagnostics to solve such problems consists of checking the site in private incognito mode and in another alternative browser. This allows you to quickly understand whether the problem lies in the settings of your specific site, or if the failure occurs at the level of your profile, extensions, or the entire operating system.

First of all, make sure that the date, time, and time zone on your computer are set absolutely correctly. If the system clock is slow or fast by even a few minutes, cryptographic security certificates will be considered invalid, which will block the connection. It is also worth checking the settings of your antivirus software, in particular the secure HTTPS connection scanning feature, which sometimes replaces certificates and causes trust errors.

If the error persists across all browsers and modes, pay attention to third-party traffic filtering programs, corporate VPN services, or corporate firewall settings. Sometimes the cause of blocking is an outdated root certificate store in your operating system that requires manual updating via Windows Update. A systematic approach to checking network parameters always helps to accurately localize and eliminate the cause of the connection failure.