diff --git a/application/src/main/java/org/thingsboard/server/actors/service/DefaultActorService.java b/application/src/main/java/org/thingsboard/server/actors/service/DefaultActorService.java
index 69061ba410..50949c1578 100644
--- a/application/src/main/java/org/thingsboard/server/actors/service/DefaultActorService.java
+++ b/application/src/main/java/org/thingsboard/server/actors/service/DefaultActorService.java
@@ -99,7 +99,7 @@ public class DefaultActorService implements ActorService {
 
     @PostConstruct
     public void initActorSystem() {
-        log.info("Initializing Actor system. {}", actorContext.getRuleChainService());
+        log.info("Initializing Actor system.");
         actorContext.setActorService(this);
         system = ActorSystem.create(ACTOR_SYSTEM_NAME, actorContext.getConfig());
         actorContext.setActorSystem(system);
diff --git a/application/src/main/java/org/thingsboard/server/controller/plugin/TbWebSocketHandler.java b/application/src/main/java/org/thingsboard/server/controller/plugin/TbWebSocketHandler.java
index c0a3ee7803..ebd068dae5 100644
--- a/application/src/main/java/org/thingsboard/server/controller/plugin/TbWebSocketHandler.java
+++ b/application/src/main/java/org/thingsboard/server/controller/plugin/TbWebSocketHandler.java
@@ -263,7 +263,7 @@ public class TbWebSocketHandler extends TextWebSocketHandler implements Telemetr
                     if (regularUserSessions.size() < maxSessionsPerRegularUser) {
                         regularUserSessions.add(sessionId);
                     } else {
-                        log.info("[{}][{}][{}] Failed to start session. Max user sessions limit reached"
+                        log.info("[{}][{}][{}] Failed to start session. Max regular user sessions limit reached"
                                 , sessionRef.getSecurityCtx().getTenantId(), sessionRef.getSecurityCtx().getId(), sessionId);
                         session.close(CloseStatus.POLICY_VIOLATION.withReason("Max regular user sessions limit reached"));
                         return false;
@@ -276,7 +276,7 @@ public class TbWebSocketHandler extends TextWebSocketHandler implements Telemetr
                     if (publicUserSessions.size() < maxSessionsPerPublicUser) {
                         publicUserSessions.add(sessionId);
                     } else {
-                        log.info("[{}][{}][{}] Failed to start session. Max user sessions limit reached"
+                        log.info("[{}][{}][{}] Failed to start session. Max public user sessions limit reached"
                                 , sessionRef.getSecurityCtx().getTenantId(), sessionRef.getSecurityCtx().getId(), sessionId);
                         session.close(CloseStatus.POLICY_VIOLATION.withReason("Max public user sessions limit reached"));
                         return false;
diff --git a/application/src/main/java/org/thingsboard/server/service/telemetry/DefaultTelemetryWebSocketService.java b/application/src/main/java/org/thingsboard/server/service/telemetry/DefaultTelemetryWebSocketService.java
index 89ecc9b910..683a8c504f 100644
--- a/application/src/main/java/org/thingsboard/server/service/telemetry/DefaultTelemetryWebSocketService.java
+++ b/application/src/main/java/org/thingsboard/server/service/telemetry/DefaultTelemetryWebSocketService.java
@@ -266,7 +266,7 @@ public class DefaultTelemetryWebSocketService implements TelemetryWebSocketServi
                         } else if (customerSessions.size() < maxSubscriptionsPerCustomer) {
                             customerSessions.add(subId);
                         } else {
-                            log.info("[{}][{}][{}] Failed to start subscription. Max customer sessions limit reached"
+                            log.info("[{}][{}][{}] Failed to start subscription. Max customer subscriptions limit reached"
                                     , sessionRef.getSecurityCtx().getTenantId(), sessionRef.getSecurityCtx().getId(), subId);
                             msgEndpoint.close(sessionRef, CloseStatus.POLICY_VIOLATION.withReason("Max customer subscriptions limit reached"));
                             return false;
@@ -279,7 +279,7 @@ public class DefaultTelemetryWebSocketService implements TelemetryWebSocketServi
                         if (regularUserSessions.size() < maxSubscriptionsPerRegularUser) {
                             regularUserSessions.add(subId);
                         } else {
-                            log.info("[{}][{}][{}] Failed to start subscription. Max user sessions limit reached"
+                            log.info("[{}][{}][{}] Failed to start subscription. Max regular user subscriptions limit reached"
                                     , sessionRef.getSecurityCtx().getTenantId(), sessionRef.getSecurityCtx().getId(), subId);
                             msgEndpoint.close(sessionRef, CloseStatus.POLICY_VIOLATION.withReason("Max regular user subscriptions limit reached"));
                             return false;
@@ -292,7 +292,7 @@ public class DefaultTelemetryWebSocketService implements TelemetryWebSocketServi
                         if (publicUserSessions.size() < maxSubscriptionsPerPublicUser) {
                             publicUserSessions.add(subId);
                         } else {
-                            log.info("[{}][{}][{}] Failed to start subscription. Max user sessions limit reached"
+                            log.info("[{}][{}][{}] Failed to start subscription. Max public user subscriptions limit reached"
                                     , sessionRef.getSecurityCtx().getTenantId(), sessionRef.getSecurityCtx().getId(), subId);
                             msgEndpoint.close(sessionRef, CloseStatus.POLICY_VIOLATION.withReason("Max public user subscriptions limit reached"));
                             return false;
diff --git a/ui/src/app/api/telemetry-websocket.service.js b/ui/src/app/api/telemetry-websocket.service.js
index 3e08e60cc1..67dec544b9 100644
--- a/ui/src/app/api/telemetry-websocket.service.js
+++ b/ui/src/app/api/telemetry-websocket.service.js
@@ -26,7 +26,7 @@ const WS_IDLE_TIMEOUT = 90000;
 const MAX_PUBLISH_COMMANDS = 10;
 
 /*@ngInject*/
-function TelemetryWebsocketService($rootScope, $websocket, $timeout, $window, types, userService) {
+function TelemetryWebsocketService($rootScope, $websocket, $timeout, $window, $mdUtil, toast, types, userService) {
 
     var isOpening = false,
         isOpened = false,
@@ -111,7 +111,10 @@ function TelemetryWebsocketService($rootScope, $websocket, $timeout, $window, ty
         }
     }
 
-    function onError (/*message*/) {
+    function onError (errorEvent) {
+        if (errorEvent) {
+            showWsError(0, errorEvent);
+        }
         isOpening = false;
     }
 
@@ -137,7 +140,10 @@ function TelemetryWebsocketService($rootScope, $websocket, $timeout, $window, ty
         }
     }
 
-    function onClose () {
+    function onClose (closeEvent) {
+        if (closeEvent && closeEvent.code > 1000 && closeEvent.code !== 1006) {
+            showWsError(closeEvent.code, closeEvent.reason);
+        }
         isOpening = false;
         isOpened = false;
         if (isActive) {
@@ -162,7 +168,9 @@ function TelemetryWebsocketService($rootScope, $websocket, $timeout, $window, ty
     function onMessage (message) {
         if (message.data) {
             var data = angular.fromJson(message.data);
-            if (data.subscriptionId) {
+            if (data.errorCode) {
+                showWsError(data.errorCode, data.errorMsg);
+            } else if (data.subscriptionId) {
                 var subscriber = subscribers[data.subscriptionId];
                 if (subscriber && data) {
                     var keys = fetchKeys(data.subscriptionId);
@@ -182,6 +190,18 @@ function TelemetryWebsocketService($rootScope, $websocket, $timeout, $window, ty
         checkToClose();
     }
 
+    function showWsError(errorCode, errorMsg) {
+        var message = 'WebSocket Error: ';
+        if (errorMsg) {
+            message += errorMsg;
+        } else {
+            message += "error code - " + errorCode + ".";
+        }
+        $mdUtil.nextTick(function () {
+            toast.showError(message);
+        });
+    }
+
     function fetchKeys(subscriptionId) {
         var command = commands[subscriptionId];
         if (command && command.keys && command.keys.length > 0) {
diff --git a/ui/src/app/common/types.constant.js b/ui/src/app/common/types.constant.js
index 506ef1d9b6..bbfca60f94 100644
--- a/ui/src/app/common/types.constant.js
+++ b/ui/src/app/common/types.constant.js
@@ -23,7 +23,9 @@ export default angular.module('thingsboard.types', [])
                 permissionDenied: 20,
                 invalidArguments: 30,
                 badRequestParams: 31,
-                itemNotFound: 32
+                itemNotFound: 32,
+                tooManyRequests: 33,
+                tooManyUpdates: 34
             },
             entryPoints: {
                 login: "/api/auth/login",
diff --git a/ui/src/app/services/toast.scss b/ui/src/app/services/toast.scss
index 952a42d855..cea79d00f7 100644
--- a/ui/src/app/services/toast.scss
+++ b/ui/src/app/services/toast.scss
@@ -16,18 +16,21 @@
 
 md-toast.tb-info-toast .md-toast-content {
   height: 100%;
+  max-height: 100%;
   padding: 18px;
   font-size: 18px;
 }
 
 md-toast.tb-success-toast .md-toast-content {
   height: 100%;
+  max-height: 100%;
   font-size: 18px !important;
   background-color: #008000;
 }
 
 md-toast.tb-error-toast .md-toast-content {
   height: 100%;
+  max-height: 100%;
   font-size: 18px !important;
   background-color: #800000;
 }