AndrzejBluszcz

I would appreciate an advice on how to connect IcsMQTTClient to PicoMQTT server on ESP8266. The server does not use SSL and serves other clients normally. IcsMQTTClient is trying to connect but with no success. The server reports that an "unknown" client connected and immediately disconnected. The client keeps connecting but nothing changes. I am using the Server / Client Demo from v.9.3 with the following properties object MQTTClient: TIcsMQTTClient ClientID = 'OverbyteClient' KeepAlive = 10 MaxRetries = 8 RetryTime = 60 Clean = True Broker = False AutoSubscribe = False Host = '192.168.1.30' Port = 1883 LocalBounce = False SslVerifyCerts = False SslReportChain = False SslRevocation = False SslCliSecurity = sslCliSecNone OnMon = MQTTClientMon OnOnline = MQTTClientOnline OnOffline = MQTTClientOffline OnEnableChange = MQTTClientEnableChange OnFailure = MQTTClientFailure OnMsg = MQTTClientMsg Left = 150 Top = 397 end Should I set some specific options in the client to enable the connection?

Thank you. I am looking forward to it. Andrzej

Thank you for your interest in my case. I am also not an expert in MQTT but at home I run a few little servers and clients on ESP microcontrollers. When I am connecting PicoMQTT client to PicoMQTT server there is no problem. I can also connect MQTT client on my iPhone and a commercial iotMQTTClient. In all cases I have empty usernames and passwords and no SSL. PicoMQTT supports v.3.1.1. Andrzej

OK. Will see. Thank you for you time and help, Mark. Andrzej

PicoMQTT supports MQTT version 3.1.1. IcsMQTTClient supports MQIsdp version 3.1 (MQTT v.3.1). So the versions on both sides are different and this the only thing that I see at the moment.

There is no response from the broker. However the broker fires OnDisconnect event. That is the broker fires OnConnect and OnDisconnect in quick succession.

It is exactly as before with one exception. The header flags are 0x10 now.

No. It didn't help. The header is correct now, though.

I think it is TIcsMQTTParser.SendConnect procedure. And it makes a header with qtAT_LEAST_ONCE, which is incorrect. I am trying to change it to qtAT_MOST_ONCE and see what happens. Andrzej

I am trying to find what sends the connect command but no success so far. Do you know where should I look for it? Andrzej

Thank you for the message. I have tried to capture the transmissions and it seems that IcsMQTTClient uses MQIsdp protocol (MQTT v.3.1) and the connection request has header flags 0x12 while another client, that connects successfully uses MQTT v.3.1.1 and the header flags 0x10. The PicoMQTT server uses MQTT v.3.1.1. Is there a way to change the behaviour of the IcsMQTTClient? I tried to replace 'MQIsdp' with 'MQTT', but that made things worse. The message is not recognised as MQTT command. Andrzej