[keycloak-user] direct access grant

Hi, I try to implements a direct access grant like a example https://keycloak.github.io/docs/userguide/keycloak-server/html/direct-acc... My client access type is confidential. On HttpResponse response = client.execute(post); I receive HTTP/1.1 400 Bad Request [Connection: keep-alive, X-Powered-By: Undertow/1, Server: WildFly/9, Transfer-Encoding: chunked, Content-Type: application/json, Date: Tue, 15 Mar 2016 08:34:36 GMT] org.apache.http.conn.BasicManagedEntity@7e3c3f85 this is my call POST /auth/realms/master/protocol/openid-connect/token HTTP/1.1 [Authorization: Basic YWRtaW46ZGFuaWVsZQ==] Content-Type: application/x-www-form-urlencoded; charset=UTF-8 this is my form params: [grant_type=password, username=a, password=a] What is wrong? Thank you Daniele