is it handled like an emergency stop from the robot if one joint is in Error mode?
Error codes: C285A0:6 (Joint_1_A); C309A0:6 (Joint_1_B); C281A3:6 (Safety_A); C281A3:6 (Safety_B)
As far as I remember, it’s a state “higher” than emergency stop actually. The robot also shuts off all 24V signals along with emergency braking the robot arm. With an emergency stop it “just” brakes the robot arm. 
Thank you for the fast response,
maybe the robot is damaged,
the manual only says reboot the robot.
The Keep Alive error is not an error I’m familiar with. I’d advise you to contact your local distributor.
You’re getting Keep Alive warnings on all joints, it seems. So I’d guess you have a defect somewhere in the cabling to the robot or in the controller.