Thank you for attaching simulation files and sorry for late reply. We had a long weekend here.
I think your simulation file is set properly. The problem is that you are using a locked mesh, which uses mesh settings of dipole example in the link below:
Error code 9002 is very general. You can find a few posts on KX that discusses how to fix this problem.
My troubleshooting steps were to fist disable heat source to see if the problem is arising from geometry/mesh building. Once I saw it is running successfully with disabled heat source, I enabled heat source and checked HEAT solver to modify max update, as is explained in this link: Heat Flow solver failed to converge after 40 iterations, error code 9002 (which you already have set it to 1000k). Simulation was still diverging.
Thanks to @aalam, we noticed that job manager shows that mesh is being loaded:
and visulazing HEAT Solver boundaries shows some boundaries with material that does not exist in this simulation, and also a zero heat power flow from +z boundary:
This indicates that mesh is locked in this simulation:
Thus, I disabled the Mesh Lock option and added proper air-Ge (Germanium) and Air- SiO2 (Glass) -Sze BCs from Material Interface. I set the scaling factor to 1 for Heat Source so that simulation is faster. Here is the result that I get:
I hope this explanation was clear and results make sense.
Please let me know if you had further questions.