My device keeps switching online and offline every few sec

[PeteKnight]

@firastayemabed78

// Your ESP8266 baud rate:
#define ESP8266_BAUD 115200

You should read this…

Understanding hardware and software serial ports

I’m still seeing frequent posts, mostly from new members of the forum, who are confused about how to add WiFi or Bluetooth connectivity to devices like the Arduino Uno, Nano or Mega, or from people who are trying to use serial communication with some other type of peripheral. I thought I’d try to put together some guidance on how to do this properly. First things first though – if you’re using a device such as an Uno, Nano or Mega that doesn’t have built-in internet connectivity then you shoul…

in particular the bit that says…

Basic Principals

Communication Speed (Baud Rate)

Your MCU board (Uno etc) and your peripheral device need to be talking to each other at the same rate. If not then they won’t be able to understand each other.

If you’re using a SoftwareSerial port to communicate with your peripheral then don’t use a baud rate higher than 9600, because the Uno etc doesn’t have enough processing power to emulate a serial port at higher communication speeds.

Pete.