[keycloak-user] Change root of activation URL

I have two services, one is my rest-service the other one is the keycloak service. When I am using the keycloak-admin-client for triggering features in keycloak like sending a verification email, I get an Email with the activation URL like: localhost:xyz auth/realms/wienenergie/login-actions/action-token? I am calling the rest-api of keycloak internally per localhost:xyz. What I wish to do is changing this internal local URL to my external URL in the admin-console. Is this possible?