"You cannot visit this site right now because the website uses HSTS"

Your browser was told, earlier, to only ever load this site over a secure connection. Now the secure connection fails, and the browser will not let you click past it.

What to do, in order

1. Check the certificate date. Most of the time the certificate expired. Renew it in your host's SSL panel, or turn auto-renew back on.
2. Check the name on the certificate. A certificate for example.com does not cover www.example.com unless both are listed. Reissue it with both names.
3. Check your computer's clock. A clock set wrong by a day makes every certificate look invalid. Fix the date and reload.
4. Visitor side only: in Chrome open chrome://net-internals/#hsts, type the domain under "Delete domain security policies", and press Delete. This only helps if the site itself is fixed.
5. Behind Cloudflare: set SSL mode to Full, and make sure the server still has its own valid certificate.

If it still fails, send me the address and I will tell you which step is broken.

Want the rest of your site checked after it is back? Run a free 40-point check at tinkeraudit.com.