diff --git a/gravitee-exchange-api/src/main/java/io/gravitee/exchange/api/controller/ControllerCommandHandlersFactory.java b/gravitee-exchange-api/src/main/java/io/gravitee/exchange/api/controller/ControllerCommandHandlersFactory.java
index d2a26bd..45d60e3 100644
--- a/gravitee-exchange-api/src/main/java/io/gravitee/exchange/api/controller/ControllerCommandHandlersFactory.java
+++ b/gravitee-exchange-api/src/main/java/io/gravitee/exchange/api/controller/ControllerCommandHandlersFactory.java
@@ -40,19 +40,23 @@ public interface ControllerCommandHandlersFactory {
      * @param controllerCommandContext the command context
      * @return a list of command decorators
      */
-    List<CommandAdapter<? extends Command<?>, ? extends Command<?>, ? extends Reply<?>>> buildCommandAdapters(
+    default List<CommandAdapter<? extends Command<?>, ? extends Command<?>, ? extends Reply<?>>> buildCommandAdapters(
         final ControllerCommandContext controllerCommandContext,
         final ProtocolVersion protocolVersion
-    );
+    ) {
+        return List.of();
+    }
 
     /**
-     * Build a list of command decorators dedicated to the specified context.
+     * Build a list of reply decorators dedicated to the specified context.
      *
      * @param controllerCommandContext the command context
-     * @return a list of command decorators
+     * @return a list of reply decorators
      */
-    List<ReplyAdapter<? extends Reply<?>, ? extends Reply<?>>> buildReplyAdapters(
+    default List<ReplyAdapter<? extends Reply<?>, ? extends Reply<?>>> buildReplyAdapters(
         final ControllerCommandContext controllerCommandContext,
         final ProtocolVersion protocolVersion
-    );
+    ) {
+        return List.of();
+    }
 }
diff --git a/gravitee-exchange-connector/gravitee-exchange-connector-core/src/main/java/io/gravitee/exchange/connector/core/DefaultExchangeConnectorManager.java b/gravitee-exchange-connector/gravitee-exchange-connector-core/src/main/java/io/gravitee/exchange/connector/core/DefaultExchangeConnectorManager.java
index 25b1aad..77ba3ff 100644
--- a/gravitee-exchange-connector/gravitee-exchange-connector-core/src/main/java/io/gravitee/exchange/connector/core/DefaultExchangeConnectorManager.java
+++ b/gravitee-exchange-connector/gravitee-exchange-connector-core/src/main/java/io/gravitee/exchange/connector/core/DefaultExchangeConnectorManager.java
@@ -68,7 +68,9 @@ public Completable register(final ExchangeConnector exchangeConnector) {
     public Completable unregister(final ExchangeConnector exchangeConnector) {
         return Completable
             .defer(() -> {
-                exchangeConnectors.remove(exchangeConnector.targetId(), exchangeConnector);
+                if (exchangeConnector.targetId() != null) {
+                    exchangeConnectors.remove(exchangeConnector.targetId(), exchangeConnector);
+                }
                 return exchangeConnector.close();
             })
             .doOnComplete(() -> log.debug("Connector successfully unregister for target [{}]", exchangeConnector.targetId()))
diff --git a/gravitee-exchange-connector/gravitee-exchange-connector-websocket/src/main/java/io/gravitee/exchange/connector/websocket/WebSocketExchangeConnector.java b/gravitee-exchange-connector/gravitee-exchange-connector-websocket/src/main/java/io/gravitee/exchange/connector/websocket/WebSocketExchangeConnector.java
index 657cad3..18392f0 100644
--- a/gravitee-exchange-connector/gravitee-exchange-connector-websocket/src/main/java/io/gravitee/exchange/connector/websocket/WebSocketExchangeConnector.java
+++ b/gravitee-exchange-connector/gravitee-exchange-connector-websocket/src/main/java/io/gravitee/exchange/connector/websocket/WebSocketExchangeConnector.java
@@ -92,7 +92,7 @@ public Completable initialize() {
                     if (err instanceof WebSocketConnectorException connectorException && connectorException.isRetryable()) {
                         return Flowable.timer(5000, TimeUnit.MILLISECONDS);
                     }
-                    log.error("Unable to connect to Exchange Connect Endpoint, stop retrying.", err);
+                    log.error("Unable to connect to Exchange Connect Endpoint, stop retrying.");
                     return Flowable.error(err);
                 })
             );
diff --git a/gravitee-exchange-connector/gravitee-exchange-connector-websocket/src/main/java/io/gravitee/exchange/connector/websocket/channel/WebSocketConnectorChannel.java b/gravitee-exchange-connector/gravitee-exchange-connector-websocket/src/main/java/io/gravitee/exchange/connector/websocket/channel/WebSocketConnectorChannel.java
index cd9e110..8d5d024 100644
--- a/gravitee-exchange-connector/gravitee-exchange-connector-websocket/src/main/java/io/gravitee/exchange/connector/websocket/channel/WebSocketConnectorChannel.java
+++ b/gravitee-exchange-connector/gravitee-exchange-connector-websocket/src/main/java/io/gravitee/exchange/connector/websocket/channel/WebSocketConnectorChannel.java
@@ -16,7 +16,6 @@
 package io.gravitee.exchange.connector.websocket.channel;
 
 import io.gravitee.exchange.api.channel.exception.ChannelException;
-import io.gravitee.exchange.api.channel.exception.ChannelInitializationException;
 import io.gravitee.exchange.api.command.Command;
 import io.gravitee.exchange.api.command.CommandAdapter;
 import io.gravitee.exchange.api.command.CommandHandler;
@@ -75,7 +74,10 @@ public Completable initialize() {
                                 this.targetId = reply.getPayload().getTargetId();
                                 this.active = true;
                             } else {
-                                throw new ChannelInitializationException("Unable to parse hello reply payload");
+                                throw new WebSocketConnectorException(
+                                    String.format("Hello handshake failed: %s", reply.getErrorDetails()),
+                                    false
+                                );
                             }
                         });
                 })