diff --git a/application/src/test/java/org/thingsboard/server/transport/mqtt/mqttv3/MqttTestClient.java b/application/src/test/java/org/thingsboard/server/transport/mqtt/mqttv3/MqttTestClient.java
index 7bd36aae4d..c4ae91a2b5 100644
--- a/application/src/test/java/org/thingsboard/server/transport/mqtt/mqttv3/MqttTestClient.java
+++ b/application/src/test/java/org/thingsboard/server/transport/mqtt/mqttv3/MqttTestClient.java
@@ -43,10 +43,6 @@ public class MqttTestClient {
         this.client = createClient();
     }
 
-    public MqttTestClient(boolean generateClientId) throws MqttException {
-        this.client = createClient(generateClientId);
-    }
-
     public MqttTestClient(String clientId) throws MqttException {
         this.client = createClient(clientId);
     }
@@ -121,18 +117,13 @@ public class MqttTestClient {
     }
 
     private MqttAsyncClient createClient() throws MqttException {
-        return createClient(true);
+        return createClient(null);
     }
 
-    private MqttAsyncClient createClient(boolean generateClientId) throws MqttException {
-        String clientId = null;
-        if (generateClientId) {
+    private MqttAsyncClient createClient(String clientId) throws MqttException {
+        if (clientId == null) {
             clientId = MqttAsyncClient.generateClientId();
         }
-        return createClient(clientId);
-    }
-
-    private MqttAsyncClient createClient(String clientId) throws MqttException {
         return new MqttAsyncClient(MQTT_URL, clientId, new MemoryPersistence());
     }
 
diff --git a/application/src/test/java/org/thingsboard/server/transport/mqtt/mqttv3/client/AbstractMqttClientConnectionTest.java b/application/src/test/java/org/thingsboard/server/transport/mqtt/mqttv3/client/AbstractMqttClientConnectionTest.java
index dd1da7ef34..634458c07d 100644
--- a/application/src/test/java/org/thingsboard/server/transport/mqtt/mqttv3/client/AbstractMqttClientConnectionTest.java
+++ b/application/src/test/java/org/thingsboard/server/transport/mqtt/mqttv3/client/AbstractMqttClientConnectionTest.java
@@ -47,13 +47,4 @@ public abstract class AbstractMqttClientConnectionTest extends AbstractMqttInteg
         }
     }
 
-    protected void processClientWithNoCredentialsTest() throws Exception {
-        MqttTestClient client = new MqttTestClient(false);
-        try {
-            client.connectAndWait();
-        } catch (MqttException e) {
-            Assert.assertEquals(MqttException.REASON_CODE_NOT_AUTHORIZED, e.getReasonCode());
-        }
-    }
-
 }
diff --git a/application/src/test/java/org/thingsboard/server/transport/mqtt/mqttv3/client/MqttClientConnectionTest.java b/application/src/test/java/org/thingsboard/server/transport/mqtt/mqttv3/client/MqttClientConnectionTest.java
index 124521eaa2..5e6e6e0188 100644
--- a/application/src/test/java/org/thingsboard/server/transport/mqtt/mqttv3/client/MqttClientConnectionTest.java
+++ b/application/src/test/java/org/thingsboard/server/transport/mqtt/mqttv3/client/MqttClientConnectionTest.java
@@ -45,9 +45,4 @@ public class MqttClientConnectionTest extends AbstractMqttClientConnectionTest {
     public void testClientWithWrongClientIdAndEmptyUsernamePassword() throws Exception {
         processClientWithWrongClientIdAndEmptyUsernamePasswordTest();
     }
-
-    @Test
-    public void testClientWithNoCredentialsTest() throws Exception {
-        processClientWithNoCredentialsTest();
-    }
 }
diff --git a/common/transport/mqtt/src/main/java/org/thingsboard/server/transport/mqtt/MqttTransportHandler.java b/common/transport/mqtt/src/main/java/org/thingsboard/server/transport/mqtt/MqttTransportHandler.java
index 2b038097a0..eee19b61a2 100644
--- a/common/transport/mqtt/src/main/java/org/thingsboard/server/transport/mqtt/MqttTransportHandler.java
+++ b/common/transport/mqtt/src/main/java/org/thingsboard/server/transport/mqtt/MqttTransportHandler.java
@@ -891,12 +891,11 @@ public class MqttTransportHandler extends ChannelInboundHandlerAdapter implement
     }
 
     private MqttConnAckMessage createMqttConnAckMsg(ReturnCode returnCode, MqttConnectMessage msg) {
-        MqttFixedHeader mqttFixedHeader =
-                new MqttFixedHeader(CONNACK, false, AT_MOST_ONCE, false, 0);
+        MqttMessageBuilders.ConnAckBuilder connAckBuilder = MqttMessageBuilders.connAck();
+        connAckBuilder.sessionPresent(!msg.variableHeader().isCleanSession());
         MqttConnectReturnCode finalReturnCode = ReturnCodeResolver.getConnectionReturnCode(deviceSessionCtx.getMqttVersion(), returnCode);
-        MqttConnAckVariableHeader mqttConnAckVariableHeader =
-                new MqttConnAckVariableHeader(finalReturnCode, !msg.variableHeader().isCleanSession());
-        return new MqttConnAckMessage(mqttFixedHeader, mqttConnAckVariableHeader);
+        connAckBuilder.returnCode(finalReturnCode);
+        return connAckBuilder.build();
     }
 
     @Override