I am new to mathlab/simulink. I try to simulate simple scheme with one resistor, ac voltage source , and electrical reference(ground). I added powergui component, solver function block(but i dont know how to attach this block and use it). Then a ran a simulation process and it terminated succesfully. But when i try to measure, for example voltage, i add voltage measurement component, and when i tried to route it to my scheme red line appeared. Why is this occur?