Pixhawk and Raspberry Pi 4 Mavlink Connection via USB ( Link 1 Down Error)

Hi Everyone,

I’m trying to connect Pixhawk Orange Cube and Raspberry Pi 4 via USB. And I watched this video " Make Your Own Pixhawk Raspberry Pi Drone in 36 Minutes (2020) | The Ultimate Project Drone - YouTube " and did exactly samething. I put a screenshot of terminal screen. As you can see there is a Link 1 Down error. Has anyone now the solution or reason of the problem.
WhatsApp Image 2022-04-23 at 3.09.18 PM

Take a look at this