SSL Flexible mode issue with the Wordpress site

I used Cloudflare Flexible mode on SSL and it worked previously without any issue. But a couple of days ago suddenly the website(Wordpress) is down and getting me “Too many redirects” error. Then I changed it to Full mode in SSL, it worked without any issue.

I’ve asked the reason from the Server hosting company (Siteground) and they said the issue is with the Cloudflare and the don’t have a reason for it. Since we using Cloudflare as a 3rd part service, they said to ask it from Cloudflare.

Did anyone experience the same or any particular reason for that?

My guess is that your host rolled out their own SSL support (or at least, told WordPress about it).

What happens is this: The browser connects to Cloudflare using HTTPS, but in Flexible mode, Cloudflare connects to WordPress using HTTP. WordPress notices this and sends a redirect to the HTTPS version. Which your browser follows, and repeat the above.

Flexible is less than ideal, Full or Strict are really the only options you should use unless you have no other choice, so this is good!

Thank you for your reply. Yes, I understood the reason.

But do you have any idea why was that happen suddenly?