No Mavlink Heartbeat Packets error

I am trying to connect Ardupilot over WSL1 with Mission Planner V4.4.0 on Windows, After creating the flight plan, I go to Simulation, choose model hexa, click on Multirotor, and download the stable SITL software. When the software is downloaded, the following error is displayed:

Do you have any idea what is happening?

I have exactly the same problem, with the last MP update (V1.3.80), connection USB is OK, but not across SiK 433 MHz radio com8 57600 bauds (last Sylabs driver) green leds solid on both, Quadrotor Pixhawk4 (telem1), arducopter V4.3.6.
That’s pity because it was worked good before ???
Please help …