Newman/node load testing silent failure

I’m trying to use newman to do some load testing. As suggested in another post, i have some powershell scripts that spawn a new instance with different csv files every 5 seconds. I seem to have hit some limit on the servers where i run the tests. When I try to spawn more than 115 instances, say 120 or 150, only 115 start, every time. The server is not bottlenecked on cpu or ram. The interesting thing is there is no error if i try to run newman or node. Even node --version returns nothing. if I kill the last couple of instances, then I can add them back. The other instances happily continue.