[keycloak-user] Keycloak behind 2 Nginx reverse proxies (HTTPS -> HTTP)

We have an idea to isolate our application in our internal network so that all communication in that network can go by HTTP. So we've set up a public nginx server, witch is responsible for establishing https connections. Public nginx server forwards requests to another nginx server in secured internal network, witch is in turn accesses Keycloak and WildFly by HTTP. But this configuration is not working because of invalid redirect issue. In our client's json file we have to define auth-server-url with HTTPS scheme. When we try to specify HTTP Keycloak no longer works. So my question: is it possible to make things work by HTTP in internal private network and HTTPS only remain for public access. Any guidance will be appreciated.