Why HFSS Optimetrics will stop before meeting the criteria

Anyone knows why HFSS Optimetrics will stop running before meeting the acceptible cost? I set the max # of iteration to 1000, but after about 40 steps, the optimectics stops with no solution. Why it stops? I appreciate it very much if anyone can explain how it works or the stop criteria of HFSS Optimetrics. Thanks.

u set maxium passes to 1000, but after each round, the mesh will be increased (default setting is 20%), that means the number of tetrahedrons will increase 20%, after it stopped at around 40 passed, what is the number of tetrahedrons? I believe it is out of RAM, so it stopped.

Best Regards,

Thanks. asdfaaa. It makes sense. I will check it.