#1 Wrong Date & Time
Your computer or device's date & time have changed to be an incorrect value. It could be sooner or later but will make your browser can't verify the SSL certificate. That said, your browser will display this error to notify you. To resolve, you need to check your date & time again and make sure they are correct.
#2 Antivirus Blocked SSL Connection
Besides the wrong date & time configuration, your antivirus software can block all SSL connections as well, especially if it has the SSL scanning feature, as seen on here. In this case, you can turn off your antivirus software temporarily to verify it's the cause or not. Also, you can locate the SSL scanning feature and turn it off.
#3 Invalid Google Chrome's Cookies & Cached Files
According to reports from users, many of them have cleared all cookies, and cached files in Google Chrome and this irritating error was gone. So, it could be caused by invalid cookies or cached files. To fix it, simply clean up all those details. Besides, resetting your Google Chrome would be helpful, but make sure you have backed up bookmarks and saved passwords. Otherwise, all those details will be deleted. You can also use Google Sync to back up those critical details.
#4 Expired SSL Certificates
Turning a website into HTTPS is to make it more secure and protect users' information. Benefits of HTTPS are real, but you also need to purchase SSL certificate to make your website work in the HTTPS version. In some cases, if the owner of the website forgot to renew the SSL certificate, you will get this error when visiting it. In this case, there is nothing you can do to get rid of it, except notify to website owner, as well as bypass it by clicking on the "Proceed" link.
#5 Invalid SSL Certificate Setup
If the website owner set up SSL certificate in wrong way, there is no way to access the HTTPS version correctly. Subsequently, you always get this error every time you access that website.
Alongside those solutions above, you can also turn off your firewall to get rid of this error (if it was caused this error). Just need to turn it off temporarily to test and then turn it on.
To turn this error message off in Google Chrome for temporary, you can add the --ignore-certificate-errors tag in the shortcut. Source