AC heat generation

Hello,

I try to convert the “Hepatic Tumor Ablation” from the Comsol library, which uses DC current and Bioheat transfer, into AC current and Bioheat transfer. Until now the electric field distribution can be plotted but I have a problem with the heat propagation.
I get the error
"Failed to find consistent initial values.
COMSOL assertion failure.
Last time step is not converged."
and I do not know how to solve it. Can anyone help me please?