ESP8266 UDP multicast doesn't receive packets
I recently had the same problem.

The unequivocal answer is that there is a power optimization (internal by Espressif) to save power, I guess, and it really creates havoc in the UDP Multicast receiving. Why? I have no idea. Same problem with the ESP32 and ESP8266.

Solution:



#include "user_interface.h"


and after:

WiFi.mode(WIFI_STA);
// the below instructions and now u will receive.
wifi_set_sleep_type(NONE_SLEEP_T); //LIGHT_SLEEP_T and MODE_SLEEP_T