Hello, the error relates to the Material Threholds. By default, perfect Insulators have conductivity<1 Siemens/m. In this case, your material cannot be simulated with these settings. In order to solve inside, change the Insulator threshold to a value that is less than the conductivity you want to simulate. To do so:
Maxwell3D>Design Settings>Material Thresholds>Insulator value
You are navigating away from the AIS Discovery experience