Meshing copper on a PCB

Hi

In the RF module I'm trying to do a simulation for a pcb with metal thickness of 18um.
The structure is a 2-port filter.
The thickness of substrate is 1.27mm.

The software simulates the structure well when I use perfect E planes instead of copper (with thickness).

But errors for meshing and boundary happens once I apply the thickness.

Is there any example or document.
Ultimately I'm going to do heat transfer analysis. Is it possible to do it with Perfect E sheets?

P.S. New to COMSOL :)

Thanks