Code for ESP8285 M2

Hi
I have this WiFi module Screenshot by Lightshot
and try to connect to Arduino Mega 2560, but when I send AT command in Serial monitore i get ? mark Screenshot by Lightshot

This is how i connect wifi module to arduino board:
EN and Vcc to 3.3V
GND to GND
TX to RX2
RX to TX2
State to pin4

Note: I've also tried more baud rates (9600, 19200, 38400, 57600, 115200) and it's always same either ?mark either or nothing.
Does anyone know where is the problem?

Does anyone know where is the problem?

It's probably in the code you didn't post.