Debug RFC destination system

Hi,

debugging production system A, I call an RFC function module in production system B, but instead of starting debugging system B, it continues debugging next step of system A.

I don't know why this is happening, I can debug both systems A and B separately, but when calling B from A, I cannot debug system B.

My user in system A is: des005

My user in system B is: des005

The passwords are not the same.

Thanks in advance