Thank you for the reply sir Pete
I’m not using any button I directly using rain sensor connect to esp8266 board and my phone already allow the notification and it is not in “do not disturb” mode. My reference making this project as in the link Youtube “Rain Alarm Notification in Mobile | IOT Projects - YouTube” and “Rain Notification Using Blynk IOT | Blynk 2.0 Notification | ESP 32 | IOT Projects - YouTube”.