No connection to PICAR-X

I have a new pica-x with a raspberry pi 4b.
WLAN is working ssh access possible.
when I try to connect EzBlock studio it connect for half a second followed be a message for disconnectet.

1、Please confirm whether the system you installed is the ezblock OS we specified?
Download link: EzblockStudio/download

If you use an app to control the robot, you must install the specified ezblock OS.
2、What kind of cell phone or tablet are you using? What is the system version of them?
And what is the version of the app?
3、When you clicked connect, did you search for Bluetooth information?
4、Please provide us with a screenshot of the connection failure.