Why does my computer freeze up while streaming video to PS4?

While streaming a movie to my PS4 using Plex Media Server, my computer become unresponsive and I am forced to perform a hard restart of my system. Once everything is restarted (Computer/PS4 Plex App/Media Server), my PS4 tells me the media server could not be reached. Each time this occurs, I go back and make sure PMS is running. Please help! My family and I would really like to enjoy Plex without repeated freeze up headaches.

Is this a re-encoding issue?
What are your system specs?