I am seeing some very strange behavior with my ESP8266. When I connect it to the WiFi for the first couple of times I am not seeing any issues and the ESP8266 connects just fine.

But after an arbitrary amount of times (like when I restart the unit) it tries to connect for AGES (like multiple minutes). Eventually it says "Connected" but the IP is completely wrong and it definitely is not connected to the router.

Here are the odd things:

• If I assign a static IP then it ALWAYS works and connects within seconds
• If I factory reset my router then it works again for a few times
• I have not seen this with any other device (like laptops or cellphones)

It is almost as if the DHCP is failing to assign an IP and then returns some random default.

#include <ESP8266WiFi.h>

// Replace these with your WiFi network settings
const char* ssid = "MYSSID"; //replace this with your WiFi network name
const char* password = "MYPASSWORD"; //replace this with your WiFi network password

void setup() {
  Serial.begin(115200);
  delay(1000);
  
  IPAddress ip(192,168,1,77);
  IPAddress gateway(192,168,1,1);
  IPAddress subnet(255,255,255,0);
  
// If I uncomment this line then it works fine
//  WiFi.config(ip, gateway, subnet);

  WiFi.begin(ssid, password);

  Serial.println();
  Serial.print("Connecting");
  
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("success!");
  Serial.print("IP Address is: ");
  Serial.println(WiFi.localIP());
}

void loop() {
  
}

When DHCP magically works it assigns: 192.168.1.159

When DHCP does not work I get: 169.254.104.241

When I use a static IP then the static IP is assigned.