Hi,
Try to use SYSTEM_THREAD(ENABLED) in your code and initialize your MQTT client like this:
MQTT client("server", 1883, callback, true); (more info about 4th par here )
also try to get rid of all of your String use snprintf() instead
example of using snprintf() on onlinegdb
#include <iostream>
using namespace std;
float Tin = 2.33897; //Tempruture
float H = 87.45; // Humidity
int alret = 5; // Alret
const char env_template[] = "\"field1=\"%.2f,\"&field2=\"%.2f,\"&field3=\"%d";
char data[sizeof(env_template) + 32 ];
void mqttpublish()
{
snprintf(data, sizeof(data), env_template, Tin, H, alret );
}
int main()
{
mqttpublish();
cout<<"env data "<<data;
return 0;
}
results:
