Your browser uses your computer’s clock to verify that a site’s SSL certificate isn’t expired. If you were already using a VPN when you first encountered the issue, on the other hand, you might try turning the VPN off, as it may be the culprit. You can also try using a Virtual Private Network (VPN) to see if the error persists. If you don’t encounter the error message, the problem is most likely with the wifi connection. Use a hotspot on your mobile device, and attempt to re-access the site. If you’re on public wifi, there’s a real possibility that your connection actually isn’t private. If you still see the error after reloading the page, check your network connection. As unlikely as it may seem, it’s possible that you just caught the website owner in the middle of renewing their SSL certificate! 2. Sometimes things just don’t work the way they should, and it’s better to try a quick fix rather than troubleshooting unnecessarily. You can also try closing and relaunching your browser, before navigating back to the same page. We may as well start with the simplest solution: Give refreshing the page a shot. You can usually proceed to the site anyway by clicking on the Advanced button, but there is some risk involved: The error text in Chrome explicitly states that your connection is not private. Let’s have a look at a few of the variations. Your operating system will also affect the exact message you see. While you’ll typically encounter the NET::ERR_CERT_DATE_INVALID error message when using Chrome, other browsers have their own version of the error. Seeing this error may also raise questions about whether your site is secure. Regardless of the reason for the error, you’ll want to fix it quickly, as it can affect traffic. In the case of this particular error, the certificate has expired. There might be a problem with the certificate itself.

This could be due to a setting, or the platform could be incompatible with the SSL certificate being used. The browser that is accessing the site is the problem.

This could include a setting on their computer, antivirus software, or the internet connection.

There’s a problem with the user’s computer.

There are a few main reasons you may see this error: While the NET::ERR_CERT_DATE_INVALID error is not unusual and can be easily fixed, it can sometimes indicate a legitimate threat. You can ignore it and click through to the page you’re trying to visit, but we don’t recommend it. In most cases, the error won’t actually prevent you from accessing the site.

The NET::ERR_CERT_DATE_INVALID error message in Firefox.

Google invalid security certificate