[Rehan]

thats kinda mixed up.

DNS and SSL are not the same. As I'm sure you all know. One can use Cloudflare DNS with either Letsencrypt ssl or cloudflare ssl. Just dont use both.
Actually you can use both too. You can configure that way and then cloudflare backend will talk to your server using letsencrypt ssl cert over https instead of plain http and you viewers will see cloudflare ssl cert on your site.

@Rehan

I updated. check my post above now.

The reason may also be a faulty plugin or .htaccess . But we will go there if the  above solutions dont work.

let us know.

Well @rudra you are right both were enabled.I have tried not by disabling the cloudflare and it is working fine now so let me try again by installing the old backup.