diff --git a/include/libwebsockets/lws-mqtt.h b/include/libwebsockets/lws-mqtt.h
index cbf8b3637..32e1d278e 100644
--- a/include/libwebsockets/lws-mqtt.h
+++ b/include/libwebsockets/lws-mqtt.h
@@ -33,6 +33,11 @@ struct lws_mqtt_str_st;
 typedef struct lws_mqtt_str_st lws_mqtt_str_t;
 
 #define MQTT_VER_3_1_1 4
+#if MQTT_VER_3_1_1 == 4
+	#define MQTT_VER_STRING "3.1.1"
+#else
+	#define MQTT_VER_STRING "unknown"
+#endif
 
 #define LWS_MQTT_FINAL_PART 1
 
diff --git a/lib/roles/mqtt/client/client-mqtt.c b/lib/roles/mqtt/client/client-mqtt.c
index ada9cffb9..8dd300a1f 100644
--- a/lib/roles/mqtt/client/client-mqtt.c
+++ b/lib/roles/mqtt/client/client-mqtt.c
@@ -338,8 +338,28 @@ lws_mqtt_client_socket_service(struct lws *wsi, struct lws_pollfd *pollfd,
 		else
 			n = lws_read_mqtt(wsi, ebuf.token, (unsigned int)ebuf.len);
 		if (n < 0) {
-			lwsl_err("%s: Parsing packet failed\n", __func__);
-			goto fail;
+			lws_mqttc_t *c = &wsi->mqtt->client;
+			char msgBuffer[128];
+			switch (c->par.reason) {
+			case LMQCP_REASON_UNSUPPORTED_PROTOCOL:
+				snprintf(msgBuffer, sizeof(msgBuffer), "reason: %s %s\n", "server does not support MQTT protocol", MQTT_VER_STRING);
+			   break;
+			case LMQCP_REASON_CLIENT_ID_INVALID:
+				snprintf(msgBuffer, sizeof(msgBuffer), "reason: %s %.*s\n", "server does not accept client ID", c->id->len, c->id->buf);
+				break;
+			case LMQCP_REASON_BAD_CREDENTIALS:
+				snprintf(msgBuffer, sizeof(msgBuffer), "reason: %s\n", "invalid credentials");
+				break;
+			case LMQCP_REASON_NOT_AUTHORIZED:
+				snprintf(msgBuffer, sizeof(msgBuffer), "reason: %s\n", "not authorized");
+				break;
+			default:
+				snprintf(msgBuffer, sizeof(msgBuffer), "reason: %s\n", "unknown MQTT connection failure");
+				break;
+			}
+			lws_inform_client_conn_fail(wsi, (void *)msgBuffer, strlen(msgBuffer));
+			lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS, __func__);
+			return -1;
 		}
 
 		m = ebuf.len - n;
diff --git a/lib/roles/mqtt/mqtt.c b/lib/roles/mqtt/mqtt.c
index 9e9dd5a80..64829050c 100644
--- a/lib/roles/mqtt/mqtt.c
+++ b/lib/roles/mqtt/mqtt.c
@@ -1029,17 +1029,27 @@ _lws_mqtt_rx_parser(struct lws *wsi, lws_mqtt_parser_t *par,
 			switch (par->conn_rc) {
 			case 0:
 				goto cmd_completion;
+			/* 3.1.1 errors [MQTT-3.2.3] */
 			case 1:
+				par->reason = LMQCP_REASON_UNSUPPORTED_PROTOCOL;
+				goto send_reason_and_close;
 			case 2:
+				par->reason = LMQCP_REASON_CLIENT_ID_INVALID;
+				goto send_reason_and_close;
 			case 3:
+				par->reason = LMQCP_REASON_SERVER_UNAVAILABLE;
+				goto send_reason_and_close;
 			case 4:
+				par->reason = LMQCP_REASON_BAD_CREDENTIALS;
+				goto send_reason_and_close;
 			case 5:
-				par->reason = LMQCP_REASON_UNSUPPORTED_PROTOCOL +
-						par->conn_rc - 1;
+				par->reason = LMQCP_REASON_NOT_AUTHORIZED;
 				goto send_reason_and_close;
+			/* 5.0 and all other errors [MQTT-3.2.2.2] */
 			default:
+				par->reason = (lws_mqtt_reason_t)par->conn_rc;
 				lwsl_notice("%s: bad connack retcode\n", __func__);
-				goto send_protocol_error_and_close;
+				goto send_reason_and_close;
 			}
 			break;