Question about defining discrete ports in CST

Hello everyone,
I am new to CST and am trying a simple structure with P/G plane and a signal line on the top layer. I defined discrete ports (in the z direction and z = the thickness of the package) at each ends of the signal line. and when I try to simulate it says discrete port in a PEC, hence terminated. Could someone help me with this. I used a background material of PEC.
Can I use waveguide ports for this kind of structure?
Thanks
Ashwini

you should change the background material from PEC to normal.
this will solve the problem
regards

Thank you. I will do that..