What to do when the microservice accesses the oidc provider internally but the user reaches the oidc provider externally?

[czephyr]

So my setup is, a frontend microservice on a container which reaches the oidc provider on the same container network by using the container name as URL like this:
http://keycloak:8081/auth/realms/myrealm/protocol/openid-connect/token

What happens then is that the user gets routed to the URL with the container name, which is not accessible from the oustide.

I couldnt figure out how to navigate this issue, any help?