xenforo users not approved after connecting to cloudflare

I installed cloudflare on my forum created with xenforo and now I cannot approve new users. It works when I turn off cloudflare. What is the reason for this?

It’s probably the Cloudflare Security level on your zone. XenForo doesn’t need it (Security Level is more for poorly designed web applications that aren’t sanitizing user input). Set your zone’s Security Level to “Essentially Off” and see if that works.