The project that I can see on your profile seems to be successfully simulated. I can also open the post processor without any problem. Do you still see a similar error while trying to access the post processor? Or is it some other project you are mentioning above? Could you please share the project URL here and also share it with support?
Everyone is able to view the post processor without any issues. I am not sure which browser or system you are using. Maybe it has something to do with that. You can run this test to see if the system is compatible: SimScale Compatibility Test Page. Let us know what it says.
Just to confirm though, could you please share the project URL? Also add a screenshot of the entire page here when you see the error!