I’m trying to run a modified version of the example for focusing grating coupler provided here https://apps.lumerical.com/pic_passive_grating_coupler_3d.html, but changing it to have elliptical gratings. I made some simulations for TE mode, and worked fine using anti-symmetric boundary layers for ymin. When I simulated for TM changing the source port 1 (fiber) to TM mode and port 2 (GC waveguide) as well, and using symmetric boundary layer this time, I get a message at the end that the simulation diverged. I also tried removing the symmetry and got the same result. I used both mesh accuracy of 3 and 4, getting the same result. Do you have any recommendations on how to troubleshoot this issue? Thank you.