Publishing wordpress site through webserver protection strips every design, features and graphic display

I've created a wordpress site that's working fine on internal network. Through webserver protection I want publish it publicly and used the setup articles for that in teh knowledge based. Everything seems to work, except for one big problem: It is published and displayed in test only. All designs, featurs, headers, etc. are stripped. So it is unusable for the public.

Any ideas what can cause this? Must be something in the UTM, because on internal network the website is working and looking fine.