Pings are failing

[buzzy]

I made a very simple test where I connect to another ESP8266 and then try to ping it. I connect correctly and get the IP 192.168.4.2 on my "slave" ESP8266. But trying ping the "master" ESP8266 on 192.168.4.1 fails. Any idea why? If I connect to the "master" ESP8266 from my laptop, I can ping it without any issues.

#include <Arduino.h>
#include <ESP8266WiFi.h>
#include <ESP8266Ping.h>

const char *ssid = "ESP8266";
const char *password = "testpassword";

IPAddress ip (192, 168, 4, 1);

void setup() {
Serial.begin(9600);

WiFi.begin(ssid, password);

while (WiFi.status() != WL_CONNECTED) { // Wait for the Wi-Fi to connect
    delay(1000);
}

Serial.println(WiFi.localIP());

}

void loop() {
bool ret = Ping.ping(ip);
if (ret) {
Serial.println("PING! PONG!");
} else {
Serial.println("Failed");
}

delay(1000);

}