Error message 'Error occurred while executing External Mode MEX-file 'ext_comm':'

I'm using the example 'Attitude Control for X-Configuration Quadcopter Using External Input' supported from the embedded coder support package for px4.

I executed the model with 'monitor and tune' button, however, I got an error message below.

Error occurred while executing External Mode MEX-file 'ext_comm':
Failed to connect to the target. Possible reasons for the failure:
a) The target is not switched on.
b) The target is not connected to your host machine.
c) The application for the model is not running on the target. You might have clicked the Stop button. If the Run button is not dimmed, click it. Otherwise, click the Build button, which downloads and runs your application on the target.

Caused by:
An error occurred attempting to open an rtIOStream. More detail may be reported in the MATLAB command window
Component:Simulink | Category:Block diagram error
Unable to connect to the 'PX4 Host Target' target for 'px4demo_AttitudeControllerWithJoystick_quadrotor'.
Component:Simulink | Category:Model error

I'm using Windows 10 and i5 CPU with 8GB RAM.

I searched my problem in MATLAB Answers, however, most articles are not focused on my situation..

Answer 1

[Ankur Bose]

The issue has been fixed in R2020b. I suggest you upgrade MATLAB to R2020b

Answer 2

[chenyue]

是不是傻逼，我2022也跑不了