In order to resolve this problem, firstly, you need to test the range of this error by using another browser, such as Firefox and load the same website. If you get a similar error message, which is: Your connection is not secure, then definitely something was wrong with your computer, not from Google Chrome.
However, if the problem is only come from Google Chrome, then you can start to diagnose and troubleshoot.
Solution #1: Clean up all cookies and cached files on your browser.
Solution #2: You can add "--ignore-certificate-errors" in the shortcut
of Google Chrome to turn off this annoying warning. This is for
temporary, not real solution to fix it.
Besides, you should also check again your date and time to make sure those settings are correct.
In case this error is appeared in both Google Chrome and Firefox (or any other web browsers), then you should take a look at your antivirus software. A feature called SSL scanning or something similar would be the cause of it.
After trying those solutions but still getting this error, I would recommend using CCleaner to uninstall Google Chrome completely and then download it again into your computer. This will help you to remove all outdated & invalid settings of Google Chrome out of your computer, which could lead to this error. However, make sure to use Google Chrome Sync to backup your sensitive data first (saved passwords).
Source: Fix Your Connection Is Not Private Error In Your Browser