Klipper cannot connect to MCU after update

hello,
Today I updated klipper, moonraker and os packages at the same time. after that I got a message that I should update the printer firmware. after updating the firmware I got the message: Printer is not ready
The klippy host software is attempting to connect. Please
retry in a few moments.

After that the connection times out.
I compiled the firmware the same way as the first time. So it should be correct.

I hope someone can help me out

I had the same and had to update the klipper firmware on the printers