RESTEASY003145: Não é possível encontrar um MessageBodyReader de aplicação tipo de conteúdo / json e tipo de classe org.keycloak.representations.AccessTokenResponse

Eu estou tentando testar Keycloak API REST. Instaled a versão 2.1.0.Final. Posso acessar o administrador através do navegador com SSL sem problemas.

Eu estou usando o código acima:

Keycloak keycloakClient = KeycloakBuilder.builder()
.serverUrl("https://keycloak.intra.rps.com.br/auth")
.realm("testrealm")
.username("development")
.password("development")
.clientId("admin-cli")
.resteasyClient(new ResteasyClientBuilder().connectionPoolSize(10).build())
.build();
List<RealmRepresentation> rr = keycloakClient.realms().findAll();

E tenho o erro:

javax.ws.rs.ProcessingException: RESTEASY003145: Unable to find a MessageBodyReader of content-type application/json and type class org.keycloak.representations.AccessTokenResponse

javax.ws.rs.client.ResponseProcessingException: javax.ws.rs.ProcessingException: RESTEASY003145: Unable to find a MessageBodyReader of content-type application/json and type class org.keycloak.representations.AccessTokenResponse
at org.jboss.resteasy.client.jaxrs.internal.ClientInvocation.extractResult(ClientInvocation.java:141)
at org.jboss.resteasy.client.jaxrs.internal.proxy.extractors.BodyEntityExtractor.extractEntity(BodyEntityExtractor.java:60)
at org.jboss.resteasy.client.jaxrs.internal.proxy.ClientInvoker.invoke(ClientInvoker.java:104)
at org.jboss.resteasy.client.jaxrs.internal.proxy.ClientProxy.invoke(ClientProxy.java:76)
at com.sun.proxy.$Proxy20.grantToken(Unknown Source)
at org.keycloak.admin.client.token.TokenManager.grantToken(TokenManager.java:85)
at org.keycloak.admin.client.token.TokenManager.getAccessToken(TokenManager.java:65)
at org.keycloak.admin.client.token.TokenManager.getAccessTokenString(TokenManager.java:60)
at org.keycloak.admin.client.resource.BearerAuthFilter.filter(BearerAuthFilter.java:52)
at org.jboss.resteasy.client.jaxrs.internal.ClientInvocation.invoke(ClientInvocation.java:413)
at org.jboss.resteasy.client.jaxrs.internal.proxy.ClientInvoker.invoke(ClientInvoker.java:102)
at org.jboss.resteasy.client.jaxrs.internal.proxy.ClientProxy.invoke(ClientProxy.java:76)
at com.sun.proxy.$Proxy22.findAll(Unknown Source)
at br.com.rps.itsm.sd.SgpKeycloakClient.doGet(SgpKeycloakClient.java:71)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:687)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85)
at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131)
at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:284)
at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:263)
at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81)
at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:174)
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:202)
at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:793)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: javax.ws.rs.ProcessingException: RESTEASY003145: Unable to find a MessageBodyReader of content-type application/json and type class org.keycloak.representations.AccessTokenResponse
at org.jboss.resteasy.core.interception.ClientReaderInterceptorContext.throwReaderNotFound(ClientReaderInterceptorContext.java:42)
at org.jboss.resteasy.core.interception.AbstractReaderInterceptorContext.getReader(AbstractReaderInterceptorContext.java:75)
at org.jboss.resteasy.core.interception.AbstractReaderInterceptorContext.proceed(AbstractReaderInterceptorContext.java:52)
at org.jboss.resteasy.plugins.interceptors.encoding.GZIPDecodingInterceptor.aroundReadFrom(GZIPDecodingInterceptor.java:59)
at org.jboss.resteasy.core.interception.AbstractReaderInterceptorContext.proceed(AbstractReaderInterceptorContext.java:55)
at org.jboss.resteasy.client.jaxrs.internal.ClientResponse.readFrom(ClientResponse.java:251)
at org.jboss.resteasy.client.jaxrs.internal.ClientResponse.readEntity(ClientResponse.java:181)
at org.jboss.resteasy.specimpl.BuiltResponse.readEntity(BuiltResponse.java:213)
at org.jboss.resteasy.client.jaxrs.internal.ClientInvocation.extractResult(ClientInvocation.java:105)

Eu adicionei as dependências acima, mas não resolver o meu problema:

    <dependency>
            <groupId>org.jboss.resteasy</groupId>
            <artifactId>resteasy-client</artifactId>
            <version>3.0.19.Final</version>
    </dependency>
    <dependency>
            <groupId>org.jboss.resteasy</groupId>
            <artifactId>resteasy-jackson-provider</artifactId>
            <version>3.0.19.Final</version>
    </dependency>

Qualquer pistas?