[keycloak-user] error in keycloak-admin-client

Hello, i update a keycloak installation from 1.7 to 1.9.1, i upgrade a pom dependency for keycloak-admin-client, bat when i call org.keycloak.admin.client.token.TokenManager.grantToken(); i receive a error org.codehaus.jackson.map.exc.UnrecognizedPropertyException: Unrecognized field "access_token" (Class org.keycloak.representations.AccessTokenResponse), not marked as ignorable at [Source: org.apache.http.conn.EofSensorInputStream@23b73091; line: 1, column: 18] (through reference chain: org.keycloak.representations.AccessTokenResponse["access_token"]) I used in my project the resteasy-client ver. 3.0.11.Final, is it possible that this library does not match with keycloak-admin-client 1.9.1-final?