Is Cloudflare removing headers?

Hello,

I just deployed a new application to our web servers, after testing the API (which requires a custom header) and after debugging the errors, it seems like after Clodflare this header is not present in the backend.

Is this something the WAF may be messing with?

Closed, turns out the web developers used apache specific functions that are not present in nginx and thus made me believe that the headers were missing, sorry for the confusion.