Error Writing to QHostAddress

[misupopo]

I am using QGroundControl.
I am having trouble communicating via MAVLink to the Pixhawk4.
My macbook and Pixhawk4 are connected via USB.

Pixhawk4 is connected to ESP8266.
ESP8266 is a wifi-module.
I reffered pixhawk4 documantation and download firmware, after that, I built the firmware site to ESP8266.

When communicating via UDP, I get an error "Error Writing to QHostAddress(192.168.4.1) 14555".
error logs will be output to the qgroundcontrol log.