Thank you for your reply.

1)
I applied the axis coordinate system using the empty prefab you mentioned. (Assets/realvirtual/Professional/IK/EmptyRobotKinematic.prefab) 

And then, it works normally. :)

2)
I have an additional question.
IK Path generation works differently in the two cases below. 

I would like to ask what settings are responsible for the difference. 

(In Case 1, the IK works with the TCP facing forward (front of the robot), and in Case 2, the IK works with the TCP facing downward (bottom of the robot).)

Case 1) ABB Robot (6-axis)
- I fine-tuned the axis positions to match the ABB IRB4400 3D model in the IK empty prefab.
(Assets/realvirtual/Professional/IK/EmptyRobotKinematic.prefab)

- Also, the Z-axis direction of the TCP was set to the front of the robot.

※ Case 1 : Robot Setting

※ Case 1 : IK Path Movement Result
→ IK Path is created with TCP facing forward (front direction of robot).
    How should I set it to look down like Case 2?

Case 2) Autonox Robot (6-axis)
- IK example prefab. (Assets/realvirtual/Professional/IK/AUTONOX/Autonox_AT_00005.prefab)

※ Case 2 : Robot Setting

※ Case 2 : IK Path Movement Result
→ IK Path is created with TCP facing down (bottom direction of robot). (Difference from Case 1)

Thanks.

Best regards,

Seokhyun Lee