I followed this guide “Problem:Keycloak - Installation of keycloak fails because - Invalid user credentials”, but this command failed
univention-keycloak --binduser "${keycloak_admin_user:-admin}" realms get
with this error message
keycloak.exceptions.KeycloakConnectionError: Can’t connect to server (HTTPSConnectionPool(host=‘ucs-sso-ng.dom.contoso.net’, port=443): Max retries exceeded with url: /realms/master/protocol/openid-connect/token (Caused by NewConnectionError(‘<urllib3.connection.HTTPSConnection object at 0x7fcb84673050>: Failed to establish a new connection: [Errno -2] Name or service not known’)))