Struggling to connect to openmqtt lilygo_rtl33

Integrations MQTT general
1

Hi I’ve installed openmqtt on lilygo_rtl433, however I’m getting issues connecting to MQTT.

Here’s my webui settings:

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And here’s mqtt explorer equivalent:
image

i can execute commands like this on linux box with no issues:
mosquitto_pub -h ‘192.168.3.104’ -t ‘W/e45f01b330f7/test’ -m ‘1’

Console output looks like this:

W: MQTT connection...
W: failure_number_mqtt: 1
W: failed, rc=-4
W: MQTT connection...
W: failure_number_mqtt: 2
W: failed, rc=-4
rtl_433_ESP(7): Average RSSI Signal -114 dbm, adjusted RSSI Threshold -105, samples 50000
W: MQTT connection...
W: failure_number_mqtt: 3

Any tips (I have tweaked source code however I’ve only edited pub_custom_topic method and tbf i have if statement that should mean my code shouldn’t run atm.

EDIT:
It has something to do with victron’s MQTT server. It connects to other mqtt brokers. Any ideas/common configs that can cause connection issues?

Could it be due to victron using protocol version mqtt5?

2

Likely mqtt5, under the covers we are using this library for the Mqtt connection, GitHub - knolleary/pubsubclient: A client library for the Arduino Ethernet Shield that provides support for MQTT.

Personally I use mosquito as my mqtt server

3

Just tested with mosquitto_pub -V 311 and 31 and can send to victron server so dont think that’s it. Any other ideas?

4

I have no issue connecting to “normal” MQTT server (0 config mosquitto server) and i can view mqtt via mqtt explorer. As you can see here, the server is receiving data from esp32 device:

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However it fails to connect on victron mqtt server. I thought maybe the initial message structure was causing the issue or maybe even mqtt version being too high on victron server but i tested using the command:

mosquitto_pub -h 192.168.3.104 -t home/T/RFtoMQTT -m ‘{“active”:3,“frequency”:433.92,“rssithreshold”:-105,“rssi”:-113,“avgrssi”:-114,“count”:0,“ookthreshold”:11}’ -V mqttv31

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5

Maybe your base topic ? I’m kinda stumped

6

Thanks for taking a look.

I’ve found where victron saves their broker logs. (FlashMQ is what they’re using).

I think I need to somehow remove username rather than sending empty string.
Guessing mosquitto is smart enough to handle this and treat as no username but maybe flashmq isnt? (Is there a quick way to edit this in the openmqtt, no worries if not i’ll just hard code it)

The logs:

[NOTICE] Accepting connection from: address='192.168.3.171', transport='TCP/Non-SSL', fd=20
@400000006634a27f14660db4 [2024-05-03 08:38:13.341] [ERROR] Unspecified or non-MQTT protocol error: Username flagged as present, but it's 0 bytes.. Removing client.
@400000006634a27f14662524 [2024-05-03 08:38:13.341] [NOTICE] Removing client '[ClientID='', username='', fd=20, keepalive=10s, transport='TCP/Non-SSL', address='192.168.3.171', prot=3.1.1, clean=0]'. Reason(s): Username flagged as present, but it's 0 bytes.
7

Or change the victron config to work similar to mosquito and allow_anonymous connections. Or define a username /password config in victrjn and the OMG config panel

8

Thanks again,
I’m reluctant to edit the Victron side as it’ll get upgraded more often than the openmqqt side (it’s C++ using flashmq which they’re recently swapped to from python so not sure how easy it is to edit/not sure it’s got config file for setting user credentials so might need to be recompiled to enable username/password every time the victron systems upgrade).

For testing I was planning on changing main.ino from:

if (client.connect(gateway_name, mqtt_user, mqtt_pass, topic, will_QoS, will_Retain, will_Message)) {

to this:

bool conn;
if(mqtt_user == "" && mqtt_pass == ""){
conn = client.connect(gateway_name, NULL, NULL, topic, will_QoS, will_Retain, will_Message);
//or is this better:
//conn = client.connect(gateway_name, topic, will_QoS, will_Retain, will_Message);

}else{
conn = client.connect(gateway_name, mqtt_user , mqtt_pass , topic, will_QoS, will_Retain, will_Message);
}

if (conn)) { 
...code continues as normal

Any red flags/issues you can spot with that plan?

9

That looks reasonable ( maybe a log entry so that you can confirm it is working correctly ? )

10

Thanks, i had to tweak it to this as they’re empty rather than empty string but this solved it, thanks again.

bool conn=false;

  if((mqtt_user == "" && mqtt_pass == "") || ((mqtt_user[0] == '\0' && mqtt_pass[0] == '\0') || (strlen(mqtt_user) == 0 && strlen(mqtt_pass) == 0))){

    conn = client.connect(gateway_name, NULL, NULL, topic, will_QoS, will_Retain, will_Message);
    Log.warning(F("NULL case" CR));
  }else{

    conn = client.connect(gateway_name, mqtt_user, mqtt_pass, topic, will_QoS, will_Retain, will_Message);
  Log.warning(F("default case" CR));
  Log.warning(F("mqttUser %s, mqttPass %s" CR), mqtt_user, mqtt_user);
  }



  if (conn) {