It often stops automatically before reaching the set number of iterations. Does anyone know why?
I stopped thinking about what you mean after 3 attempts, so yes 
But it sounds like the good old “out of memory” error
Can you post your Generative Design Log file? Should be called RefineryServerLog if memory serves. The exact location can be tough to pinpoint if we don’t know what build you’re on (click the ? in generative design to find out), but if you can’t find it yourself let us know what build you are using and I will have a look.
Rename that log file, recreate the problem (make sure when you start generative design there are no studies running, close them down by hitting stop and/or restart your CPU as needed), and post the new log, the DYN you are sending, and a screenshot(s) showing your study setup.
I will reach out to development on Monday after I try to recreate the issue with those materials.