"Your connection is not private"

The website's security certificate, the thing behind the padlock, isn't valid: it has run out, it's for a different address, or it's set up wrongly. Your browser can't be sure it's talking to the real site, so it stops you.

What you'll see

Chrome and Edge
Your connection is not private, with a code such as NET::ERR_CERT_DATE_INVALID (run out), NET::ERR_CERT_COMMON_NAME_INVALID (for a different address) or NET::ERR_CERT_AUTHORITY_INVALID.
Safari
This Connection Is Not Private.
Firefox
Warning: Potential Security Risk Ahead.

If you're visiting a site

  1. Don't type passwords or card details on that site until it's fixed.
  2. Check your computer's date and time are right: a wrong clock makes every certificate look invalid.
  3. Try another network. Hotel, airport and café Wi-Fi sometimes cause this before you've logged in to the Wi-Fi page.
  4. If only one site shows it, it's that site's problem. Contact the business another way and tell them.

Stuck, and someone's helping you? Send them your details with My setup, or a screenshot and the error messages with PageKiwi for Chrome.

If it's your site

  1. Run Site health. It shows your certificate's end date and whether it matches your address.
  2. Ask your web host to renew or reissue the certificate. On most hosts it's free (Let's Encrypt or AutoSSL) and should renew itself, but renewals can fail quietly.
  3. If the warning mentions a different name, the certificate doesn't cover the address people use: often the www. version or the plain one. Ask your host to cover both.
  4. Sign up to Site Watch, so you get an email 14 days before it runs out next time.

Tools that help: Site health, Site Watch, What "Not secure" means.