“Your connection is not private” is a Chrome wording of the failed security check on the site certificate.
The issue could be about https vs. http, or similar Transport Layer Security URL. Unless it is your own bookmark (you could use http instead, without the expectation of security), there is little you can do about it. Often it is something the site owner must do to fix it (Revoked certificate/old certificate; Mix of https and http in a single webpage; etc.).
Other reasons for a failed secure connection between the user and the server:
- If time and date are off too much, the security check of the certificate will fail. Set the time correctly.
- 3rd party “security” monitoring software (anti malware, anti virus, privacy, etc.) may reject a secure connection on wrong assumptions or settings. Don’t use such software.
- Browser caches/Website Data could be a cause for disrupted functionality. Removing such data may fix that.
- Not the latest version of the software. Relaunch with updated version of the app, to get the latest security fixes.
- A VPN tunnel may be misunderstood by some of the components as a MITM.
And lastly, there is a choice to bypass it, if you are confident that the message is not describing a thread in your situation (Advanced > Continue to site). Generally not recommended!