ams simulation does not work with large number of design points

Hello,

In my simulation using ams, I sweep a variable.
when this sweep ends up with 3 or 5 design points, it works.
But when I increase the range or reduce the step, which give me larger number of design points like 21 or 27, it keeps showing pending in the result tab even after left it over night.
I did not change other thing beside this one variable that I want to sweep.
The circuit contains mostly analog part with just one block written in verilog.
The  analog part works well with Spectre.

Is there something I can try?

Virtuoso IC6.1.8-64b.500.14
Xcellium 20.09-s001
Spectre  19.1.0 64bit

1 point simulation takes 2.5 minute.
5 design points, it works. it takes around 15 minutes.


25 design points, it does not work. I left it over night.


9 design points, it does not work. I put here to show how it looks like before I stop the simulation after 35 minutes.