How can i activated mavlink in my px4 again?

I have px4 and I am working UAV motion control with matlab. UAV Toolbox Support Package for PX4 Autopilots. I installed the UAV Toolbox Support Package for PX4 Autopilots and set up to matlab. matlab turned off the mavlink protocol by default. my computer does not recognize the px4 as an ardupilot device. USB serial device (COM9) is written on the port. how can I restore it?

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