AJAX requests causing reset of ESP8266

[kdobrev]

I am trying to execute the following function, but my ESP crashes as soon as I press the button calling the function. It does not seem to enter any server.on();

function send_comand(gsm_number) {
var xhttp = new XMLHttpRequest;
xhttp.open("POST", "/", true);
xhttp.send("action=erasen&gsm1=" + gsm_number);
// window.location = window.location;
}

[me-no-dev]

I see no Arduino/AsyncServer code here? maybe show us that as well?