What error shows up to you?
Moreover, do you use any caching plugin with WordPress like W3 Total Cache?
Also, what option have you selected for “Cache” at Cloudflare dashboard?
Cache Everything maybe? (either general or on a Page Rule)
Do you have an SSL certificate installed at your host/origin for your domain and sub-domain(s) (like www, etc.)?
Which SSL option have you got selected under SSL tab/settings page at Cloudflare dashboard for your domain?
Is the WordPress installed on HTTP or HTTPS? (check the HOME URL and SITE URL values)
Do you also use some plugin to redirect, like Really Simple SSL?
Should look like this if using W3 Total Cache with Cloudflare:
Maybe you have got
Flexible SSL option selected and your WordPress was obviously installed on HTTP, that could be a reason why you see them.
Here is a good article about why Flexible SSL is not a “win-win”:
Could you check the steps in the below article?: