ESP8266 Community Forum

- Wed Jul 15, 2020 1:51 am #87903 Hi

I have wrote a sketch in which I connect my esp8266-07 to CloudMQTT broker. In my code I'm always checking whether my esp is connected to the broker or not. I use client.connected() for this matter.

first question:
there are sometimes that ESP gets disconnected (client.state() == -4). what are the causes of this problem? why this happens more that 4 times in a minute???? My internet connection is stable!

second question:
sometimes when I'm using client.connect(ID, username, pass); ESP freezes for 10 or 15 seconds and then it doesn't connect the broker (client.state() == -2) . why this is happening and more importantly, how can I pass this delay?????

I don't know whether my code helps you to find the solution or not but this is my function. this function is called in every main loop and gets functional in every other 60 loops thanks to the variable time_out:

Code: Select allvoid make_connection(void)
{

  if (time_out == 1)
  {
    switch (connect_cycle_stat)
    {
      case 0:
        {
          Serial.printf("\nmake_connection ==>");
          Serial.printf("\ncase %d. ", connect_cycle_stat);
          if (WiFi.softAP(ap_ssid, ap_pass))
          {
            server.begin();
            connect_cycle_stat++;
            time_out = 0;
          }
          break;
        }

      case 1:
        {
          Serial.printf("\nmake_connection ==>");
          Serial.printf("\ncase %d. ", connect_cycle_stat);
          Serial.printf("\nWiFi.status() = %d", WiFi.status());
          if (WiFi.status() == WL_CONNECTED)
          {
            time_out   = 0;
            connect_cycle_stat++;

            uint8_t mac[6];
            WiFi.macAddress(mac);
            device_ID += macToStr(mac);
            //update_esp();
          }
          else
          {
            WiFi.begin(wifi_ssid, wifi_pass);
          }
          break;
        }

      case 2:
        {
          Serial.printf("\nmake_connection ==>");
          Serial.printf("\ncase %d. ", connect_cycle_stat);
          Serial.printf("\nmqtt_client.connected() = %d", mqtt_client.connected());
          Serial.printf("\nWiFi.status() = %d", WiFi.status());
          if (mqtt_client.connected() == true)
          {
            mqtt_client.publish(out_topic.c_str(), "Hello from ESP8266");
            mqtt_client.subscribe("steamer/appClient");
            // will handle the incoming messages for the topics subscribed.
            mqtt_client.setCallback(callback);
            connect_cycle_stat++;
          }
          else
          {
            //mqtt_client.disconnect();
            delay(100);
            mqtt_client.connect(device_ID.c_str(), mqtt_user, mqtt_pass);
          }
          break;
        }

      case 3:
        {
          Serial.printf("\nmake_connection ==>");
          Serial.printf("\ncase %d. ", connect_cycle_stat);
          Serial.printf("\nmqtt_client.connected() = %d", mqtt_client.connected());
          Serial.printf("\nWiFi.status() = %d", WiFi.status());
          if (mqtt_client.connected() == false)
          {
            //mqtt_client.disconnect();
            delay(100);
            connect_cycle_stat--;
          }

          if (WiFi.status() != WL_CONNECTED)
          {
            WiFi.begin(wifi_ssid, wifi_pass);
            connect_cycle_stat = 1;
          }
          break;
        }
    }
  }
  time_out++;
  if (time_out > 60) time_out = 0;
}



- Wed Jul 15, 2020 2:43 am #87905 "My internet connection is stable!" - we would all love that to be true, but there are many reasons why it never can be. Even if it was true, the server connection would also need to be stable... Error -4 means thaat there is no connection with the server, so only 2 things are possible:
1) There is a problem with the internet connection between you and the server, which has many possible causes
2) There is a problem with the server
3) Your code is failing and not maintaining the connection, which again has multiple possible causes.

If 3) then it it very difficult to diagnose the problem without seeing a) all the code b) any error messages. The code you show is how you are handling the reconnects, but not what might be causing the disconnects, which is what we need to see.

One tiny point: I would use a much longer delay between reconnect attempts - say, 5 seconds.

One of the reasons I changed from pubsubclient is the 5 second "freeze" when it reconnects. Because you are waiting only 100 mS between attempts you will "queue up" maybe 3 attempts berfore it actually connects and 3x5s = 15 seconds etc.

There are alternative libraries to pubsubclient that do not "freeze" on reconnect, look at : https://github.com/philbowles/PangolinMQTT