You’ll have to narrow it down. There’s probably a single proxy file which is causing the crash. So keep deleting certain types until it doesn’t crash and you’ll find the one that’s causing it. Then pull that proxy into a clean scene and see if it crashes - if it does, something is wrong with it and you’ll have to take a look over the model in your original source scene.
Unfortunately this is just something we have to do from time to time!
I think the problem was NOT related to the proxies - After trying to solve the problem for more than 24 hours - I changed 1 (ONE) parameter and it solved the issue:
I increased the dynamic RAM amount.
as of this moment - it is rendering with much higher settings and much quicker.