Which of your products do you view as most likely to have led to the termination?

I don’t mean, which do you agree or consider just cause for leading to it. But as the operator of them, you are best positioned to estimate which one(s) a risk-avoidant corporation would be most likely reacting to, and knowing more about your actual circumstances would be valuable anecdata for others trying to help (as well as those reconsidering Vercel!).