If you want your site only to be accessible via HTTPS then you use strict, use .htaccess or Cloudflare to redirect all traffic from HTTP to HTTPS. Strict will not work correct if you have not installed the SSL cert correctly on your server, since strict means the origin server (your hosting) most have a valid SSL.
You should disable Cloudflare temporary in the DNS settings within the Cloudflare dashboard then use a SSL labs to test the CERT install.
After you validated the issue you should force redirect using either Apache or Cloudflare, below is the Cloudflare page rule, should you want CF to handle it.
Cloudflare Page Rule 301 Redirect from HTTP to HTTPS
- Login to Cloudflare
- Select your site using the dropdown menu found in the upper left corner
- Click the Page Rules icon at the top of the screen
- Click the Create Page Rule button
- Enter http://example.com/ but obviously changing the domain with yours.
- Under “Then the settings are:” click + Add a Setting
- Click the dropdown list, find and click option “Always Use HTTPS”
- Finally click Save and Deploy
If you are getting mixed issues warnings then you will need to edit your content or template files to remove all traces of absolute URLS with
HTTP:// and replace either