diff --git a/Sming/SmingCore/Network/MqttClient.cpp b/Sming/SmingCore/Network/MqttClient.cpp
index 33c6e02902..0c5d19538f 100644
--- a/Sming/SmingCore/Network/MqttClient.cpp
+++ b/Sming/SmingCore/Network/MqttClient.cpp
@@ -77,6 +77,10 @@ bool MqttClient::setWill(const String& topic, const String& message, int QoS, bo
 bool MqttClient::connect(const URL& url, const String& clientName, uint32_t sslOptions)
 {
 	this->url = url;
+	if (not (url.Protocol == "mqtt" || url.Protocol == "mqtts")) {
+		debug_e("Only mqtt and mqtts protocols are allowed");
+		return false;
+	}
 	waitingSize = 0;
 	posHeader = 0;
 	current = NULL;
diff --git a/Sming/SmingCore/Network/MqttClient.h b/Sming/SmingCore/Network/MqttClient.h
index d247c3033e..d2985842ee 100644
--- a/Sming/SmingCore/Network/MqttClient.h
+++ b/Sming/SmingCore/Network/MqttClient.h
@@ -55,7 +55,7 @@ class MqttClient: protected TcpClient
 	bool setWill(const String& topic, const String& message, int QoS, bool retained = false);
 
 	/** @brief  Connect to a MQTT server
-	*  @param  url, in the form "mttqs://user:password@server:port"
+	*  @param  url, in the form "mqtt://user:password@server:port" or "mqtts://user:password@server:port"
 	*  @param  client name
 	*/
 	bool connect(const URL& url, const String& uniqueClientName, uint32_t sslOptions = 0);