Can you turn on MultiVehicleManagerLog as described here: https://docs.qgroundcontrol.com/en/Support/Support.html. Then connect and post the console log output.
I have the same issue for a while now. Could you take a look at console log output and see what the issue is? Also as I have formatted the SD card by following the procedure without any good.
Thank you for your time.
QGC is not seeing any connections. Please move this to a QGC GitHub Issue. And provide details as to how you are connecting as well: usb, sik radio, wifi, ...
Oh, and you could use "PrtScrn"-Key for Screenshots that are actually readable