Cannot set hostname for ESP8266 - dns

Question

I am facing a problem, as setting host name for my ESP8266 is not working. Even though when I'm trying to connect through default host name "ESP_xxxx", it's not working.
Actually when I upload my code with my mobile hotspot SSID and password then it's working fine, but as soon as I gave the SSID and password of my router then it's not working.
Here's my code (setup part):
#include <ESP8266WiFi.h>
const char* ssid = "xxxxxx";
const char* password = "xxxxxx";
int ledPin = 13; // GPIO13
WiFiServer server(80);
void setup() {
Serial.begin(115200);
delay(10);
pinMode(ledPin, OUTPUT);
digitalWrite(ledPin, LOW);
// Connect to WiFi network
Serial.println();
Serial.println();
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.hostname("xyz");
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.println("WiFi connected");
// Start the server
server.begin();
Serial.println("Server started");
// Print the IP address
Serial.print("Use this URL to connect: ");
Serial.print("http://");
Serial.print(WiFi.localIP());
Serial.println("/");
Serial.println(WiFi.hostname());
}

Answer 1

Try this:
#include <ESP8266WiFi.h> //https://github.com/esp8266/Arduino
//
#include <DNSServer.h>
#include <ESP8266WebServer.h>
#include "WiFiManager.h" //https://github.com/tzapu/WiFiManager
void configModeCallback (WiFiManager *myWiFiManager)
{
Serial.println("Entered config mode");
Serial.println(WiFi.softAPIP());
Serial.println(myWiFiManager->getConfigPortalSSID());
}
//
void setup()
{
Serial.begin(115200);
//
WiFiManager wifiManager;
WiFi.hostname("myhostname");
//
//wifiManager.resetSettings();
//
//
wifiManager.setAPCallback(configModeCallback);
if (!wifiManager.autoConnect("myhostname"))
{
Serial.println("failed to connect and hit timeout");
// reset
ESP.reset();
delay(1000);
}
//
Serial.println("connected...yeey :)");
}
void loop()
{
//
}

Answer 2

Stumbled upon this issue and below is the code which works for me.
WiFi.disconnect(true);
WiFi.begin(ssid, password);
WiFi.setHostname(device);`
Also came across below code, with this line the module is not receiving any IP. Hence deleted it.
WiFi.config(INADDR_NONE, INADDR_NONE, INADDR_NONE);
Running on Arduino 1.8.15 and esp8266 board version 3.0.1

Answer 3

Try using mDNS instead.
Include the mDNS library
#include <ESP8266mDNS.h>
Then in the setup after you connected to WiFi, start mDNS like this.
if (!MDNS.begin("your-desired-hostname")) {
Serial.println("Error setting up MDNS responder!");
}