Different simulation settings can be related to convergence issues in CHARGE. Based on the information you shared I have the following suggestions:
1 – Please make sure the applied voltage starts from 0 V and the voltage step is reasonably small (e.g. 0.25 V, 0.5V).
2 – If at any point you have some partial results to read (for example if the simulation stops in second step) try looking into the field and current results. Is there a rapid increase in current or an extremely high field value observed? In such cases increasing the iteration limit in the advanced settings can be helpful.
3 – Try replacing the circle object with rectangle. If this fixes the error the issue might be related to meshing issues for curved objects. Adding local mesh constraints or replacing the circle with polygon could be useful then.
4 – Try replacing the domain 3 material with a material from database (e.g. silicon). In some cases the material can make obtaining convergence more difficult (for example for materials with large bandgap). If you find that this fixes the error, try looking into the advanced settings and increasing the iteration number to see if it will fix the error.
5 – Finally, please share your mesh settings (available in the solver mesh tab) and the dimensions of your objects so I can comment more specifically on whether the mesh refinement should be adjusted.
Hope this will help you. If you have any new information about your simulation, please let me know.